1 /*
   2  * Copyright (c) 2005, 2022, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "compiler/compileLog.hpp"
  27 #include "gc/shared/collectedHeap.inline.hpp"
  28 #include "gc/shared/tlab_globals.hpp"
  29 #include "libadt/vectset.hpp"
  30 #include "memory/universe.hpp"
  31 #include "opto/addnode.hpp"
  32 #include "opto/arraycopynode.hpp"
  33 #include "opto/callnode.hpp"
  34 #include "opto/castnode.hpp"
  35 #include "opto/cfgnode.hpp"
  36 #include "opto/compile.hpp"
  37 #include "opto/convertnode.hpp"
  38 #include "opto/graphKit.hpp"
  39 #include "opto/intrinsicnode.hpp"
  40 #include "opto/locknode.hpp"
  41 #include "opto/loopnode.hpp"
  42 #include "opto/macro.hpp"
  43 #include "opto/memnode.hpp"
  44 #include "opto/narrowptrnode.hpp"
  45 #include "opto/node.hpp"
  46 #include "opto/opaquenode.hpp"
  47 #include "opto/phaseX.hpp"
  48 #include "opto/rootnode.hpp"
  49 #include "opto/runtime.hpp"
  50 #include "opto/subnode.hpp"
  51 #include "opto/subtypenode.hpp"
  52 #include "opto/type.hpp"
  53 #include "prims/jvmtiExport.hpp"
  54 #include "runtime/continuation.hpp"
  55 #include "runtime/sharedRuntime.hpp"
  56 #include "utilities/macros.hpp"
  57 #include "utilities/powerOfTwo.hpp"
  58 #if INCLUDE_G1GC
  59 #include "gc/g1/g1ThreadLocalData.hpp"
  60 #endif // INCLUDE_G1GC
  61 #if INCLUDE_SHENANDOAHGC
  62 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
  63 #endif
  64 
  65 
  66 //
  67 // Replace any references to "oldref" in inputs to "use" with "newref".
  68 // Returns the number of replacements made.
  69 //
  70 int PhaseMacroExpand::replace_input(Node *use, Node *oldref, Node *newref) {
  71   int nreplacements = 0;
  72   uint req = use->req();
  73   for (uint j = 0; j < use->len(); j++) {
  74     Node *uin = use->in(j);
  75     if (uin == oldref) {
  76       if (j < req)
  77         use->set_req(j, newref);
  78       else
  79         use->set_prec(j, newref);
  80       nreplacements++;
  81     } else if (j >= req && uin == NULL) {
  82       break;
  83     }
  84   }
  85   return nreplacements;
  86 }
  87 
  88 void PhaseMacroExpand::migrate_outs(Node *old, Node *target) {
  89   assert(old != NULL, "sanity");
  90   for (DUIterator_Fast imax, i = old->fast_outs(imax); i < imax; i++) {
  91     Node* use = old->fast_out(i);
  92     _igvn.rehash_node_delayed(use);
  93     imax -= replace_input(use, old, target);
  94     // back up iterator
  95     --i;
  96   }
  97   assert(old->outcnt() == 0, "all uses must be deleted");
  98 }
  99 
 100 Node* PhaseMacroExpand::opt_bits_test(Node* ctrl, Node* region, int edge, Node* word, int mask, int bits, bool return_fast_path) {
 101   Node* cmp;
 102   if (mask != 0) {
 103     Node* and_node = transform_later(new AndXNode(word, MakeConX(mask)));
 104     cmp = transform_later(new CmpXNode(and_node, MakeConX(bits)));
 105   } else {
 106     cmp = word;
 107   }
 108   Node* bol = transform_later(new BoolNode(cmp, BoolTest::ne));
 109   IfNode* iff = new IfNode( ctrl, bol, PROB_MIN, COUNT_UNKNOWN );
 110   transform_later(iff);
 111 
 112   // Fast path taken.
 113   Node *fast_taken = transform_later(new IfFalseNode(iff));
 114 
 115   // Fast path not-taken, i.e. slow path
 116   Node *slow_taken = transform_later(new IfTrueNode(iff));
 117 
 118   if (return_fast_path) {
 119     region->init_req(edge, slow_taken); // Capture slow-control
 120     return fast_taken;
 121   } else {
 122     region->init_req(edge, fast_taken); // Capture fast-control
 123     return slow_taken;
 124   }
 125 }
 126 
 127 //--------------------copy_predefined_input_for_runtime_call--------------------
 128 void PhaseMacroExpand::copy_predefined_input_for_runtime_call(Node * ctrl, CallNode* oldcall, CallNode* call) {
 129   // Set fixed predefined input arguments
 130   call->init_req( TypeFunc::Control, ctrl );
 131   call->init_req( TypeFunc::I_O    , oldcall->in( TypeFunc::I_O) );
 132   call->init_req( TypeFunc::Memory , oldcall->in( TypeFunc::Memory ) ); // ?????
 133   call->init_req( TypeFunc::ReturnAdr, oldcall->in( TypeFunc::ReturnAdr ) );
 134   call->init_req( TypeFunc::FramePtr, oldcall->in( TypeFunc::FramePtr ) );
 135 }
 136 
 137 //------------------------------make_slow_call---------------------------------
 138 CallNode* PhaseMacroExpand::make_slow_call(CallNode *oldcall, const TypeFunc* slow_call_type,
 139                                            address slow_call, const char* leaf_name, Node* slow_path,
 140                                            Node* parm0, Node* parm1, Node* parm2) {
 141 
 142   // Slow-path call
 143  CallNode *call = leaf_name
 144    ? (CallNode*)new CallLeafNode      ( slow_call_type, slow_call, leaf_name, TypeRawPtr::BOTTOM )
 145    : (CallNode*)new CallStaticJavaNode( slow_call_type, slow_call, OptoRuntime::stub_name(slow_call), TypeRawPtr::BOTTOM );
 146 
 147   // Slow path call has no side-effects, uses few values
 148   copy_predefined_input_for_runtime_call(slow_path, oldcall, call );
 149   if (parm0 != NULL)  call->init_req(TypeFunc::Parms+0, parm0);
 150   if (parm1 != NULL)  call->init_req(TypeFunc::Parms+1, parm1);
 151   if (parm2 != NULL)  call->init_req(TypeFunc::Parms+2, parm2);
 152   call->copy_call_debug_info(&_igvn, oldcall);
 153   call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
 154   _igvn.replace_node(oldcall, call);
 155   transform_later(call);
 156 
 157   return call;
 158 }
 159 
 160 void PhaseMacroExpand::eliminate_gc_barrier(Node* p2x) {
 161   BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
 162   bs->eliminate_gc_barrier(this, p2x);
 163 #ifndef PRODUCT
 164   if (PrintOptoStatistics) {
 165     Atomic::inc(&PhaseMacroExpand::_GC_barriers_removed_counter);
 166   }
 167 #endif
 168 }
 169 
 170 // Search for a memory operation for the specified memory slice.
 171 static Node *scan_mem_chain(Node *mem, int alias_idx, int offset, Node *start_mem, Node *alloc, PhaseGVN *phase) {
 172   Node *orig_mem = mem;
 173   Node *alloc_mem = alloc->in(TypeFunc::Memory);
 174   const TypeOopPtr *tinst = phase->C->get_adr_type(alias_idx)->isa_oopptr();
 175   while (true) {
 176     if (mem == alloc_mem || mem == start_mem ) {
 177       return mem;  // hit one of our sentinels
 178     } else if (mem->is_MergeMem()) {
 179       mem = mem->as_MergeMem()->memory_at(alias_idx);
 180     } else if (mem->is_Proj() && mem->as_Proj()->_con == TypeFunc::Memory) {
 181       Node *in = mem->in(0);
 182       // we can safely skip over safepoints, calls, locks and membars because we
 183       // already know that the object is safe to eliminate.
 184       if (in->is_Initialize() && in->as_Initialize()->allocation() == alloc) {
 185         return in;
 186       } else if (in->is_Call()) {
 187         CallNode *call = in->as_Call();
 188         if (call->may_modify(tinst, phase)) {
 189           assert(call->is_ArrayCopy(), "ArrayCopy is the only call node that doesn't make allocation escape");
 190           if (call->as_ArrayCopy()->modifies(offset, offset, phase, false)) {
 191             return in;
 192           }
 193         }
 194         mem = in->in(TypeFunc::Memory);
 195       } else if (in->is_MemBar()) {
 196         ArrayCopyNode* ac = NULL;
 197         if (ArrayCopyNode::may_modify(tinst, in->as_MemBar(), phase, ac)) {
 198           if (ac != NULL) {
 199             assert(ac->is_clonebasic(), "Only basic clone is a non escaping clone");
 200             return ac;
 201           }
 202         }
 203         mem = in->in(TypeFunc::Memory);
 204       } else {
 205 #ifdef ASSERT
 206         in->dump();
 207         mem->dump();
 208         assert(false, "unexpected projection");
 209 #endif
 210       }
 211     } else if (mem->is_Store()) {
 212       const TypePtr* atype = mem->as_Store()->adr_type();
 213       int adr_idx = phase->C->get_alias_index(atype);
 214       if (adr_idx == alias_idx) {
 215         assert(atype->isa_oopptr(), "address type must be oopptr");
 216         int adr_offset = atype->offset();
 217         uint adr_iid = atype->is_oopptr()->instance_id();
 218         // Array elements references have the same alias_idx
 219         // but different offset and different instance_id.
 220         if (adr_offset == offset && adr_iid == alloc->_idx) {
 221           return mem;
 222         }
 223       } else {
 224         assert(adr_idx == Compile::AliasIdxRaw, "address must match or be raw");
 225       }
 226       mem = mem->in(MemNode::Memory);
 227     } else if (mem->is_ClearArray()) {
 228       if (!ClearArrayNode::step_through(&mem, alloc->_idx, phase)) {
 229         // Can not bypass initialization of the instance
 230         // we are looking.
 231         debug_only(intptr_t offset;)
 232         assert(alloc == AllocateNode::Ideal_allocation(mem->in(3), phase, offset), "sanity");
 233         InitializeNode* init = alloc->as_Allocate()->initialization();
 234         // We are looking for stored value, return Initialize node
 235         // or memory edge from Allocate node.
 236         if (init != NULL) {
 237           return init;
 238         } else {
 239           return alloc->in(TypeFunc::Memory); // It will produce zero value (see callers).
 240         }
 241       }
 242       // Otherwise skip it (the call updated 'mem' value).
 243     } else if (mem->Opcode() == Op_SCMemProj) {
 244       mem = mem->in(0);
 245       Node* adr = NULL;
 246       if (mem->is_LoadStore()) {
 247         adr = mem->in(MemNode::Address);
 248       } else {
 249         assert(mem->Opcode() == Op_EncodeISOArray ||
 250                mem->Opcode() == Op_StrCompressedCopy, "sanity");
 251         adr = mem->in(3); // Destination array
 252       }
 253       const TypePtr* atype = adr->bottom_type()->is_ptr();
 254       int adr_idx = phase->C->get_alias_index(atype);
 255       if (adr_idx == alias_idx) {
 256         DEBUG_ONLY(mem->dump();)
 257         assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
 258         return NULL;
 259       }
 260       mem = mem->in(MemNode::Memory);
 261    } else if (mem->Opcode() == Op_StrInflatedCopy) {
 262       Node* adr = mem->in(3); // Destination array
 263       const TypePtr* atype = adr->bottom_type()->is_ptr();
 264       int adr_idx = phase->C->get_alias_index(atype);
 265       if (adr_idx == alias_idx) {
 266         DEBUG_ONLY(mem->dump();)
 267         assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
 268         return NULL;
 269       }
 270       mem = mem->in(MemNode::Memory);
 271     } else {
 272       return mem;
 273     }
 274     assert(mem != orig_mem, "dead memory loop");
 275   }
 276 }
 277 
 278 // Generate loads from source of the arraycopy for fields of
 279 // destination needed at a deoptimization point
 280 Node* PhaseMacroExpand::make_arraycopy_load(ArrayCopyNode* ac, intptr_t offset, Node* ctl, Node* mem, BasicType ft, const Type *ftype, AllocateNode *alloc) {
 281   BasicType bt = ft;
 282   const Type *type = ftype;
 283   if (ft == T_NARROWOOP) {
 284     bt = T_OBJECT;
 285     type = ftype->make_oopptr();
 286   }
 287   Node* res = NULL;
 288   if (ac->is_clonebasic()) {
 289     assert(ac->in(ArrayCopyNode::Src) != ac->in(ArrayCopyNode::Dest), "clone source equals destination");
 290     Node* base = ac->in(ArrayCopyNode::Src);
 291     Node* adr = _igvn.transform(new AddPNode(base, base, MakeConX(offset)));
 292     const TypePtr* adr_type = _igvn.type(base)->is_ptr()->add_offset(offset);
 293     MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
 294     BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 295     res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
 296   } else {
 297     if (ac->modifies(offset, offset, &_igvn, true)) {
 298       assert(ac->in(ArrayCopyNode::Dest) == alloc->result_cast(), "arraycopy destination should be allocation's result");
 299       uint shift = exact_log2(type2aelembytes(bt));
 300       Node* src_pos = ac->in(ArrayCopyNode::SrcPos);
 301       Node* dest_pos = ac->in(ArrayCopyNode::DestPos);
 302       const TypeInt* src_pos_t = _igvn.type(src_pos)->is_int();
 303       const TypeInt* dest_pos_t = _igvn.type(dest_pos)->is_int();
 304 
 305       Node* adr = NULL;
 306       const TypePtr* adr_type = NULL;
 307       if (src_pos_t->is_con() && dest_pos_t->is_con()) {
 308         intptr_t off = ((src_pos_t->get_con() - dest_pos_t->get_con()) << shift) + offset;
 309         Node* base = ac->in(ArrayCopyNode::Src);
 310         adr = _igvn.transform(new AddPNode(base, base, MakeConX(off)));
 311         adr_type = _igvn.type(base)->is_ptr()->add_offset(off);
 312         if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
 313           // Don't emit a new load from src if src == dst but try to get the value from memory instead
 314           return value_from_mem(ac->in(TypeFunc::Memory), ctl, ft, ftype, adr_type->isa_oopptr(), alloc);
 315         }
 316       } else {
 317         Node* diff = _igvn.transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos)));
 318 #ifdef _LP64
 319         diff = _igvn.transform(new ConvI2LNode(diff));
 320 #endif
 321         diff = _igvn.transform(new LShiftXNode(diff, intcon(shift)));
 322 
 323         Node* off = _igvn.transform(new AddXNode(MakeConX(offset), diff));
 324         Node* base = ac->in(ArrayCopyNode::Src);
 325         adr = _igvn.transform(new AddPNode(base, base, off));
 326         adr_type = _igvn.type(base)->is_ptr()->add_offset(Type::OffsetBot);
 327         if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
 328           // Non constant offset in the array: we can't statically
 329           // determine the value
 330           return NULL;
 331         }
 332       }
 333       MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
 334       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 335       res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
 336     }
 337   }
 338   if (res != NULL) {
 339     if (ftype->isa_narrowoop()) {
 340       // PhaseMacroExpand::scalar_replacement adds DecodeN nodes
 341       res = _igvn.transform(new EncodePNode(res, ftype));
 342     }
 343     return res;
 344   }
 345   return NULL;
 346 }
 347 
 348 //
 349 // Given a Memory Phi, compute a value Phi containing the values from stores
 350 // on the input paths.
 351 // Note: this function is recursive, its depth is limited by the "level" argument
 352 // Returns the computed Phi, or NULL if it cannot compute it.
 353 Node *PhaseMacroExpand::value_from_mem_phi(Node *mem, BasicType ft, const Type *phi_type, const TypeOopPtr *adr_t, AllocateNode *alloc, Node_Stack *value_phis, int level) {
 354   assert(mem->is_Phi(), "sanity");
 355   int alias_idx = C->get_alias_index(adr_t);
 356   int offset = adr_t->offset();
 357   int instance_id = adr_t->instance_id();
 358 
 359   // Check if an appropriate value phi already exists.
 360   Node* region = mem->in(0);
 361   for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
 362     Node* phi = region->fast_out(k);
 363     if (phi->is_Phi() && phi != mem &&
 364         phi->as_Phi()->is_same_inst_field(phi_type, (int)mem->_idx, instance_id, alias_idx, offset)) {
 365       return phi;
 366     }
 367   }
 368   // Check if an appropriate new value phi already exists.
 369   Node* new_phi = value_phis->find(mem->_idx);
 370   if (new_phi != NULL)
 371     return new_phi;
 372 
 373   if (level <= 0) {
 374     return NULL; // Give up: phi tree too deep
 375   }
 376   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
 377   Node *alloc_mem = alloc->in(TypeFunc::Memory);
 378 
 379   uint length = mem->req();
 380   GrowableArray <Node *> values(length, length, NULL);
 381 
 382   // create a new Phi for the value
 383   PhiNode *phi = new PhiNode(mem->in(0), phi_type, NULL, mem->_idx, instance_id, alias_idx, offset);
 384   transform_later(phi);
 385   value_phis->push(phi, mem->_idx);
 386 
 387   for (uint j = 1; j < length; j++) {
 388     Node *in = mem->in(j);
 389     if (in == NULL || in->is_top()) {
 390       values.at_put(j, in);
 391     } else  {
 392       Node *val = scan_mem_chain(in, alias_idx, offset, start_mem, alloc, &_igvn);
 393       if (val == start_mem || val == alloc_mem) {
 394         // hit a sentinel, return appropriate 0 value
 395         values.at_put(j, _igvn.zerocon(ft));
 396         continue;
 397       }
 398       if (val->is_Initialize()) {
 399         val = val->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
 400       }
 401       if (val == NULL) {
 402         return NULL;  // can't find a value on this path
 403       }
 404       if (val == mem) {
 405         values.at_put(j, mem);
 406       } else if (val->is_Store()) {
 407         Node* n = val->in(MemNode::ValueIn);
 408         BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 409         n = bs->step_over_gc_barrier(n);
 410         if (is_subword_type(ft)) {
 411           n = Compile::narrow_value(ft, n, phi_type, &_igvn, true);
 412         }
 413         values.at_put(j, n);
 414       } else if(val->is_Proj() && val->in(0) == alloc) {
 415         values.at_put(j, _igvn.zerocon(ft));
 416       } else if (val->is_Phi()) {
 417         val = value_from_mem_phi(val, ft, phi_type, adr_t, alloc, value_phis, level-1);
 418         if (val == NULL) {
 419           return NULL;
 420         }
 421         values.at_put(j, val);
 422       } else if (val->Opcode() == Op_SCMemProj) {
 423         assert(val->in(0)->is_LoadStore() ||
 424                val->in(0)->Opcode() == Op_EncodeISOArray ||
 425                val->in(0)->Opcode() == Op_StrCompressedCopy, "sanity");
 426         assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
 427         return NULL;
 428       } else if (val->is_ArrayCopy()) {
 429         Node* res = make_arraycopy_load(val->as_ArrayCopy(), offset, val->in(0), val->in(TypeFunc::Memory), ft, phi_type, alloc);
 430         if (res == NULL) {
 431           return NULL;
 432         }
 433         values.at_put(j, res);
 434       } else {
 435         DEBUG_ONLY( val->dump(); )
 436         assert(false, "unknown node on this path");
 437         return NULL;  // unknown node on this path
 438       }
 439     }
 440   }
 441   // Set Phi's inputs
 442   for (uint j = 1; j < length; j++) {
 443     if (values.at(j) == mem) {
 444       phi->init_req(j, phi);
 445     } else {
 446       phi->init_req(j, values.at(j));
 447     }
 448   }
 449   return phi;
 450 }
 451 
 452 // Search the last value stored into the object's field.
 453 Node *PhaseMacroExpand::value_from_mem(Node *sfpt_mem, Node *sfpt_ctl, BasicType ft, const Type *ftype, const TypeOopPtr *adr_t, AllocateNode *alloc) {
 454   assert(adr_t->is_known_instance_field(), "instance required");
 455   int instance_id = adr_t->instance_id();
 456   assert((uint)instance_id == alloc->_idx, "wrong allocation");
 457 
 458   int alias_idx = C->get_alias_index(adr_t);
 459   int offset = adr_t->offset();
 460   Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
 461   Node *alloc_ctrl = alloc->in(TypeFunc::Control);
 462   Node *alloc_mem = alloc->in(TypeFunc::Memory);
 463   VectorSet visited;
 464 
 465   bool done = sfpt_mem == alloc_mem;
 466   Node *mem = sfpt_mem;
 467   while (!done) {
 468     if (visited.test_set(mem->_idx)) {
 469       return NULL;  // found a loop, give up
 470     }
 471     mem = scan_mem_chain(mem, alias_idx, offset, start_mem, alloc, &_igvn);
 472     if (mem == start_mem || mem == alloc_mem) {
 473       done = true;  // hit a sentinel, return appropriate 0 value
 474     } else if (mem->is_Initialize()) {
 475       mem = mem->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
 476       if (mem == NULL) {
 477         done = true; // Something go wrong.
 478       } else if (mem->is_Store()) {
 479         const TypePtr* atype = mem->as_Store()->adr_type();
 480         assert(C->get_alias_index(atype) == Compile::AliasIdxRaw, "store is correct memory slice");
 481         done = true;
 482       }
 483     } else if (mem->is_Store()) {
 484       const TypeOopPtr* atype = mem->as_Store()->adr_type()->isa_oopptr();
 485       assert(atype != NULL, "address type must be oopptr");
 486       assert(C->get_alias_index(atype) == alias_idx &&
 487              atype->is_known_instance_field() && atype->offset() == offset &&
 488              atype->instance_id() == instance_id, "store is correct memory slice");
 489       done = true;
 490     } else if (mem->is_Phi()) {
 491       // try to find a phi's unique input
 492       Node *unique_input = NULL;
 493       Node *top = C->top();
 494       for (uint i = 1; i < mem->req(); i++) {
 495         Node *n = scan_mem_chain(mem->in(i), alias_idx, offset, start_mem, alloc, &_igvn);
 496         if (n == NULL || n == top || n == mem) {
 497           continue;
 498         } else if (unique_input == NULL) {
 499           unique_input = n;
 500         } else if (unique_input != n) {
 501           unique_input = top;
 502           break;
 503         }
 504       }
 505       if (unique_input != NULL && unique_input != top) {
 506         mem = unique_input;
 507       } else {
 508         done = true;
 509       }
 510     } else if (mem->is_ArrayCopy()) {
 511       done = true;
 512     } else {
 513       DEBUG_ONLY( mem->dump(); )
 514       assert(false, "unexpected node");
 515     }
 516   }
 517   if (mem != NULL) {
 518     if (mem == start_mem || mem == alloc_mem) {
 519       // hit a sentinel, return appropriate 0 value
 520       return _igvn.zerocon(ft);
 521     } else if (mem->is_Store()) {
 522       Node* n = mem->in(MemNode::ValueIn);
 523       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 524       n = bs->step_over_gc_barrier(n);
 525       return n;
 526     } else if (mem->is_Phi()) {
 527       // attempt to produce a Phi reflecting the values on the input paths of the Phi
 528       Node_Stack value_phis(8);
 529       Node* phi = value_from_mem_phi(mem, ft, ftype, adr_t, alloc, &value_phis, ValueSearchLimit);
 530       if (phi != NULL) {
 531         return phi;
 532       } else {
 533         // Kill all new Phis
 534         while(value_phis.is_nonempty()) {
 535           Node* n = value_phis.node();
 536           _igvn.replace_node(n, C->top());
 537           value_phis.pop();
 538         }
 539       }
 540     } else if (mem->is_ArrayCopy()) {
 541       Node* ctl = mem->in(0);
 542       Node* m = mem->in(TypeFunc::Memory);
 543       if (sfpt_ctl->is_Proj() && sfpt_ctl->as_Proj()->is_uncommon_trap_proj(Deoptimization::Reason_none)) {
 544         // pin the loads in the uncommon trap path
 545         ctl = sfpt_ctl;
 546         m = sfpt_mem;
 547       }
 548       return make_arraycopy_load(mem->as_ArrayCopy(), offset, ctl, m, ft, ftype, alloc);
 549     }
 550   }
 551   // Something go wrong.
 552   return NULL;
 553 }
 554 
 555 // Check the possibility of scalar replacement.
 556 bool PhaseMacroExpand::can_eliminate_allocation(AllocateNode *alloc, GrowableArray <SafePointNode *>& safepoints) {
 557   //  Scan the uses of the allocation to check for anything that would
 558   //  prevent us from eliminating it.
 559   NOT_PRODUCT( const char* fail_eliminate = NULL; )
 560   DEBUG_ONLY( Node* disq_node = NULL; )
 561   bool  can_eliminate = true;
 562 
 563   Node* res = alloc->result_cast();
 564   const TypeOopPtr* res_type = NULL;
 565   if (res == NULL) {
 566     // All users were eliminated.
 567   } else if (!res->is_CheckCastPP()) {
 568     NOT_PRODUCT(fail_eliminate = "Allocation does not have unique CheckCastPP";)
 569     can_eliminate = false;
 570   } else {
 571     res_type = _igvn.type(res)->isa_oopptr();
 572     if (res_type == NULL) {
 573       NOT_PRODUCT(fail_eliminate = "Neither instance or array allocation";)
 574       can_eliminate = false;
 575     } else if (res_type->isa_aryptr()) {
 576       int length = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 577       if (length < 0) {
 578         NOT_PRODUCT(fail_eliminate = "Array's size is not constant";)
 579         can_eliminate = false;
 580       }
 581     }
 582   }
 583 
 584   if (can_eliminate && res != NULL) {
 585     for (DUIterator_Fast jmax, j = res->fast_outs(jmax);
 586                                j < jmax && can_eliminate; j++) {
 587       Node* use = res->fast_out(j);
 588 
 589       if (use->is_AddP()) {
 590         const TypePtr* addp_type = _igvn.type(use)->is_ptr();
 591         int offset = addp_type->offset();
 592 
 593         if (offset == Type::OffsetTop || offset == Type::OffsetBot) {
 594           NOT_PRODUCT(fail_eliminate = "Undefined field reference";)
 595           can_eliminate = false;
 596           break;
 597         }
 598         for (DUIterator_Fast kmax, k = use->fast_outs(kmax);
 599                                    k < kmax && can_eliminate; k++) {
 600           Node* n = use->fast_out(k);
 601           if (!n->is_Store() && n->Opcode() != Op_CastP2X
 602               SHENANDOAHGC_ONLY(&& (!UseShenandoahGC || !ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(n))) ) {
 603             DEBUG_ONLY(disq_node = n;)
 604             if (n->is_Load() || n->is_LoadStore()) {
 605               NOT_PRODUCT(fail_eliminate = "Field load";)
 606             } else {
 607               NOT_PRODUCT(fail_eliminate = "Not store field reference";)
 608             }
 609             can_eliminate = false;
 610           }
 611         }
 612       } else if (use->is_ArrayCopy() &&
 613                  (use->as_ArrayCopy()->is_clonebasic() ||
 614                   use->as_ArrayCopy()->is_arraycopy_validated() ||
 615                   use->as_ArrayCopy()->is_copyof_validated() ||
 616                   use->as_ArrayCopy()->is_copyofrange_validated()) &&
 617                  use->in(ArrayCopyNode::Dest) == res) {
 618         // ok to eliminate
 619       } else if (use->is_SafePoint()) {
 620         SafePointNode* sfpt = use->as_SafePoint();
 621         if (sfpt->is_Call() && sfpt->as_Call()->has_non_debug_use(res)) {
 622           // Object is passed as argument.
 623           DEBUG_ONLY(disq_node = use;)
 624           NOT_PRODUCT(fail_eliminate = "Object is passed as argument";)
 625           can_eliminate = false;
 626         }
 627         Node* sfptMem = sfpt->memory();
 628         if (sfptMem == NULL || sfptMem->is_top()) {
 629           DEBUG_ONLY(disq_node = use;)
 630           NOT_PRODUCT(fail_eliminate = "NULL or TOP memory";)
 631           can_eliminate = false;
 632         } else {
 633           safepoints.append_if_missing(sfpt);
 634         }
 635       } else if (use->Opcode() != Op_CastP2X) { // CastP2X is used by card mark
 636         if (use->is_Phi()) {
 637           if (use->outcnt() == 1 && use->unique_out()->Opcode() == Op_Return) {
 638             NOT_PRODUCT(fail_eliminate = "Object is return value";)
 639           } else {
 640             NOT_PRODUCT(fail_eliminate = "Object is referenced by Phi";)
 641           }
 642           DEBUG_ONLY(disq_node = use;)
 643         } else {
 644           if (use->Opcode() == Op_Return) {
 645             NOT_PRODUCT(fail_eliminate = "Object is return value";)
 646           }else {
 647             NOT_PRODUCT(fail_eliminate = "Object is referenced by node";)
 648           }
 649           DEBUG_ONLY(disq_node = use;)
 650         }
 651         can_eliminate = false;
 652       }
 653     }
 654   }
 655 
 656 #ifndef PRODUCT
 657   if (PrintEliminateAllocations) {
 658     if (can_eliminate) {
 659       tty->print("Scalar ");
 660       if (res == NULL)
 661         alloc->dump();
 662       else
 663         res->dump();
 664     } else if (alloc->_is_scalar_replaceable) {
 665       tty->print("NotScalar (%s)", fail_eliminate);
 666       if (res == NULL)
 667         alloc->dump();
 668       else
 669         res->dump();
 670 #ifdef ASSERT
 671       if (disq_node != NULL) {
 672           tty->print("  >>>> ");
 673           disq_node->dump();
 674       }
 675 #endif /*ASSERT*/
 676     }
 677   }
 678 #endif
 679   return can_eliminate;
 680 }
 681 
 682 // Do scalar replacement.
 683 bool PhaseMacroExpand::scalar_replacement(AllocateNode *alloc, GrowableArray <SafePointNode *>& safepoints) {
 684   GrowableArray <SafePointNode *> safepoints_done;
 685 
 686   ciInstanceKlass* iklass = NULL;
 687   int nfields = 0;
 688   int array_base = 0;
 689   int element_size = 0;
 690   BasicType basic_elem_type = T_ILLEGAL;
 691   const Type* field_type = NULL;
 692 
 693   Node* res = alloc->result_cast();
 694   assert(res == NULL || res->is_CheckCastPP(), "unexpected AllocateNode result");
 695   const TypeOopPtr* res_type = NULL;
 696   if (res != NULL) { // Could be NULL when there are no users
 697     res_type = _igvn.type(res)->isa_oopptr();
 698   }
 699 
 700   if (res != NULL) {
 701     if (res_type->isa_instptr()) {
 702       // find the fields of the class which will be needed for safepoint debug information
 703       iklass = res_type->is_instptr()->instance_klass();
 704       nfields = iklass->nof_nonstatic_fields();
 705     } else {
 706       // find the array's elements which will be needed for safepoint debug information
 707       nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
 708       assert(nfields >= 0, "must be an array klass.");
 709       basic_elem_type = res_type->is_aryptr()->elem()->array_element_basic_type();
 710       array_base = arrayOopDesc::base_offset_in_bytes(basic_elem_type);
 711       element_size = type2aelembytes(basic_elem_type);
 712       field_type = res_type->is_aryptr()->elem();
 713     }
 714   }
 715   //
 716   // Process the safepoint uses
 717   //
 718   while (safepoints.length() > 0) {
 719     SafePointNode* sfpt = safepoints.pop();
 720     Node* mem = sfpt->memory();
 721     Node* ctl = sfpt->control();
 722     assert(sfpt->jvms() != NULL, "missed JVMS");
 723     // Fields of scalar objs are referenced only at the end
 724     // of regular debuginfo at the last (youngest) JVMS.
 725     // Record relative start index.
 726     uint first_ind = (sfpt->req() - sfpt->jvms()->scloff());
 727     SafePointScalarObjectNode* sobj = new SafePointScalarObjectNode(res_type,
 728 #ifdef ASSERT
 729                                                  alloc,
 730 #endif
 731                                                  first_ind, nfields);
 732     sobj->init_req(0, C->root());
 733     transform_later(sobj);
 734 
 735     // Scan object's fields adding an input to the safepoint for each field.
 736     for (int j = 0; j < nfields; j++) {
 737       intptr_t offset;
 738       ciField* field = NULL;
 739       if (iklass != NULL) {
 740         field = iklass->nonstatic_field_at(j);
 741         offset = field->offset();
 742         ciType* elem_type = field->type();
 743         basic_elem_type = field->layout_type();
 744 
 745         // The next code is taken from Parse::do_get_xxx().
 746         if (is_reference_type(basic_elem_type)) {
 747           if (!elem_type->is_loaded()) {
 748             field_type = TypeInstPtr::BOTTOM;
 749           } else if (field != NULL && field->is_static_constant()) {
 750             ciObject* con = field->constant_value().as_object();
 751             // Do not "join" in the previous type; it doesn't add value,
 752             // and may yield a vacuous result if the field is of interface type.
 753             field_type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
 754             assert(field_type != NULL, "field singleton type must be consistent");
 755           } else {
 756             field_type = TypeOopPtr::make_from_klass(elem_type->as_klass());
 757           }
 758           if (UseCompressedOops) {
 759             field_type = field_type->make_narrowoop();
 760             basic_elem_type = T_NARROWOOP;
 761           }
 762         } else {
 763           field_type = Type::get_const_basic_type(basic_elem_type);
 764         }
 765       } else {
 766         offset = array_base + j * (intptr_t)element_size;
 767       }
 768 
 769       const TypeOopPtr *field_addr_type = res_type->add_offset(offset)->isa_oopptr();
 770 
 771       Node *field_val = value_from_mem(mem, ctl, basic_elem_type, field_type, field_addr_type, alloc);
 772       if (field_val == NULL) {
 773         // We weren't able to find a value for this field,
 774         // give up on eliminating this allocation.
 775 
 776         // Remove any extra entries we added to the safepoint.
 777         uint last = sfpt->req() - 1;
 778         for (int k = 0;  k < j; k++) {
 779           sfpt->del_req(last--);
 780         }
 781         _igvn._worklist.push(sfpt);
 782         // rollback processed safepoints
 783         while (safepoints_done.length() > 0) {
 784           SafePointNode* sfpt_done = safepoints_done.pop();
 785           // remove any extra entries we added to the safepoint
 786           last = sfpt_done->req() - 1;
 787           for (int k = 0;  k < nfields; k++) {
 788             sfpt_done->del_req(last--);
 789           }
 790           JVMState *jvms = sfpt_done->jvms();
 791           jvms->set_endoff(sfpt_done->req());
 792           // Now make a pass over the debug information replacing any references
 793           // to SafePointScalarObjectNode with the allocated object.
 794           int start = jvms->debug_start();
 795           int end   = jvms->debug_end();
 796           for (int i = start; i < end; i++) {
 797             if (sfpt_done->in(i)->is_SafePointScalarObject()) {
 798               SafePointScalarObjectNode* scobj = sfpt_done->in(i)->as_SafePointScalarObject();
 799               if (scobj->first_index(jvms) == sfpt_done->req() &&
 800                   scobj->n_fields() == (uint)nfields) {
 801                 assert(scobj->alloc() == alloc, "sanity");
 802                 sfpt_done->set_req(i, res);
 803               }
 804             }
 805           }
 806           _igvn._worklist.push(sfpt_done);
 807         }
 808 #ifndef PRODUCT
 809         if (PrintEliminateAllocations) {
 810           if (field != NULL) {
 811             tty->print("=== At SafePoint node %d can't find value of Field: ",
 812                        sfpt->_idx);
 813             field->print();
 814             int field_idx = C->get_alias_index(field_addr_type);
 815             tty->print(" (alias_idx=%d)", field_idx);
 816           } else { // Array's element
 817             tty->print("=== At SafePoint node %d can't find value of array element [%d]",
 818                        sfpt->_idx, j);
 819           }
 820           tty->print(", which prevents elimination of: ");
 821           if (res == NULL)
 822             alloc->dump();
 823           else
 824             res->dump();
 825         }
 826 #endif
 827         return false;
 828       }
 829       if (UseCompressedOops && field_type->isa_narrowoop()) {
 830         // Enable "DecodeN(EncodeP(Allocate)) --> Allocate" transformation
 831         // to be able scalar replace the allocation.
 832         if (field_val->is_EncodeP()) {
 833           field_val = field_val->in(1);
 834         } else {
 835           field_val = transform_later(new DecodeNNode(field_val, field_val->get_ptr_type()));
 836         }
 837       }
 838       sfpt->add_req(field_val);
 839     }
 840     JVMState *jvms = sfpt->jvms();
 841     jvms->set_endoff(sfpt->req());
 842     // Now make a pass over the debug information replacing any references
 843     // to the allocated object with "sobj"
 844     int start = jvms->debug_start();
 845     int end   = jvms->debug_end();
 846     sfpt->replace_edges_in_range(res, sobj, start, end, &_igvn);
 847     _igvn._worklist.push(sfpt);
 848     safepoints_done.append_if_missing(sfpt); // keep it for rollback
 849   }
 850   return true;
 851 }
 852 
 853 static void disconnect_projections(MultiNode* n, PhaseIterGVN& igvn) {
 854   Node* ctl_proj = n->proj_out_or_null(TypeFunc::Control);
 855   Node* mem_proj = n->proj_out_or_null(TypeFunc::Memory);
 856   if (ctl_proj != NULL) {
 857     igvn.replace_node(ctl_proj, n->in(0));
 858   }
 859   if (mem_proj != NULL) {
 860     igvn.replace_node(mem_proj, n->in(TypeFunc::Memory));
 861   }
 862 }
 863 
 864 // Process users of eliminated allocation.
 865 void PhaseMacroExpand::process_users_of_allocation(CallNode *alloc) {
 866   Node* res = alloc->result_cast();
 867   if (res != NULL) {
 868     for (DUIterator_Last jmin, j = res->last_outs(jmin); j >= jmin; ) {
 869       Node *use = res->last_out(j);
 870       uint oc1 = res->outcnt();
 871 
 872       if (use->is_AddP()) {
 873         for (DUIterator_Last kmin, k = use->last_outs(kmin); k >= kmin; ) {
 874           Node *n = use->last_out(k);
 875           uint oc2 = use->outcnt();
 876           if (n->is_Store()) {
 877 #ifdef ASSERT
 878             // Verify that there is no dependent MemBarVolatile nodes,
 879             // they should be removed during IGVN, see MemBarNode::Ideal().
 880             for (DUIterator_Fast pmax, p = n->fast_outs(pmax);
 881                                        p < pmax; p++) {
 882               Node* mb = n->fast_out(p);
 883               assert(mb->is_Initialize() || !mb->is_MemBar() ||
 884                      mb->req() <= MemBarNode::Precedent ||
 885                      mb->in(MemBarNode::Precedent) != n,
 886                      "MemBarVolatile should be eliminated for non-escaping object");
 887             }
 888 #endif
 889             _igvn.replace_node(n, n->in(MemNode::Memory));
 890           } else {
 891             eliminate_gc_barrier(n);
 892           }
 893           k -= (oc2 - use->outcnt());
 894         }
 895         _igvn.remove_dead_node(use);
 896       } else if (use->is_ArrayCopy()) {
 897         // Disconnect ArrayCopy node
 898         ArrayCopyNode* ac = use->as_ArrayCopy();
 899         if (ac->is_clonebasic()) {
 900           Node* membar_after = ac->proj_out(TypeFunc::Control)->unique_ctrl_out();
 901           disconnect_projections(ac, _igvn);
 902           assert(alloc->in(TypeFunc::Memory)->is_Proj() && alloc->in(TypeFunc::Memory)->in(0)->Opcode() == Op_MemBarCPUOrder, "mem barrier expected before allocation");
 903           Node* membar_before = alloc->in(TypeFunc::Memory)->in(0);
 904           disconnect_projections(membar_before->as_MemBar(), _igvn);
 905           if (membar_after->is_MemBar()) {
 906             disconnect_projections(membar_after->as_MemBar(), _igvn);
 907           }
 908         } else {
 909           assert(ac->is_arraycopy_validated() ||
 910                  ac->is_copyof_validated() ||
 911                  ac->is_copyofrange_validated(), "unsupported");
 912           CallProjections callprojs;
 913           ac->extract_projections(&callprojs, true);
 914 
 915           _igvn.replace_node(callprojs.fallthrough_ioproj, ac->in(TypeFunc::I_O));
 916           _igvn.replace_node(callprojs.fallthrough_memproj, ac->in(TypeFunc::Memory));
 917           _igvn.replace_node(callprojs.fallthrough_catchproj, ac->in(TypeFunc::Control));
 918 
 919           // Set control to top. IGVN will remove the remaining projections
 920           ac->set_req(0, top());
 921           ac->replace_edge(res, top(), &_igvn);
 922 
 923           // Disconnect src right away: it can help find new
 924           // opportunities for allocation elimination
 925           Node* src = ac->in(ArrayCopyNode::Src);
 926           ac->replace_edge(src, top(), &_igvn);
 927           // src can be top at this point if src and dest of the
 928           // arraycopy were the same
 929           if (src->outcnt() == 0 && !src->is_top()) {
 930             _igvn.remove_dead_node(src);
 931           }
 932         }
 933         _igvn._worklist.push(ac);
 934       } else {
 935         eliminate_gc_barrier(use);
 936       }
 937       j -= (oc1 - res->outcnt());
 938     }
 939     assert(res->outcnt() == 0, "all uses of allocated objects must be deleted");
 940     _igvn.remove_dead_node(res);
 941   }
 942 
 943   //
 944   // Process other users of allocation's projections
 945   //
 946   if (_callprojs.resproj != NULL && _callprojs.resproj->outcnt() != 0) {
 947     // First disconnect stores captured by Initialize node.
 948     // If Initialize node is eliminated first in the following code,
 949     // it will kill such stores and DUIterator_Last will assert.
 950     for (DUIterator_Fast jmax, j = _callprojs.resproj->fast_outs(jmax);  j < jmax; j++) {
 951       Node* use = _callprojs.resproj->fast_out(j);
 952       if (use->is_AddP()) {
 953         // raw memory addresses used only by the initialization
 954         _igvn.replace_node(use, C->top());
 955         --j; --jmax;
 956       }
 957     }
 958     for (DUIterator_Last jmin, j = _callprojs.resproj->last_outs(jmin); j >= jmin; ) {
 959       Node* use = _callprojs.resproj->last_out(j);
 960       uint oc1 = _callprojs.resproj->outcnt();
 961       if (use->is_Initialize()) {
 962         // Eliminate Initialize node.
 963         InitializeNode *init = use->as_Initialize();
 964         assert(init->outcnt() <= 2, "only a control and memory projection expected");
 965         Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
 966         if (ctrl_proj != NULL) {
 967           _igvn.replace_node(ctrl_proj, init->in(TypeFunc::Control));
 968 #ifdef ASSERT
 969           // If the InitializeNode has no memory out, it will die, and tmp will become NULL
 970           Node* tmp = init->in(TypeFunc::Control);
 971           assert(tmp == NULL || tmp == _callprojs.fallthrough_catchproj, "allocation control projection");
 972 #endif
 973         }
 974         Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
 975         if (mem_proj != NULL) {
 976           Node *mem = init->in(TypeFunc::Memory);
 977 #ifdef ASSERT
 978           if (mem->is_MergeMem()) {
 979             assert(mem->in(TypeFunc::Memory) == _callprojs.fallthrough_memproj, "allocation memory projection");
 980           } else {
 981             assert(mem == _callprojs.fallthrough_memproj, "allocation memory projection");
 982           }
 983 #endif
 984           _igvn.replace_node(mem_proj, mem);
 985         }
 986       } else  {
 987         assert(false, "only Initialize or AddP expected");
 988       }
 989       j -= (oc1 - _callprojs.resproj->outcnt());
 990     }
 991   }
 992   if (_callprojs.fallthrough_catchproj != NULL) {
 993     _igvn.replace_node(_callprojs.fallthrough_catchproj, alloc->in(TypeFunc::Control));
 994   }
 995   if (_callprojs.fallthrough_memproj != NULL) {
 996     _igvn.replace_node(_callprojs.fallthrough_memproj, alloc->in(TypeFunc::Memory));
 997   }
 998   if (_callprojs.catchall_memproj != NULL) {
 999     _igvn.replace_node(_callprojs.catchall_memproj, C->top());
1000   }
1001   if (_callprojs.fallthrough_ioproj != NULL) {
1002     _igvn.replace_node(_callprojs.fallthrough_ioproj, alloc->in(TypeFunc::I_O));
1003   }
1004   if (_callprojs.catchall_ioproj != NULL) {
1005     _igvn.replace_node(_callprojs.catchall_ioproj, C->top());
1006   }
1007   if (_callprojs.catchall_catchproj != NULL) {
1008     _igvn.replace_node(_callprojs.catchall_catchproj, C->top());
1009   }
1010 }
1011 
1012 bool PhaseMacroExpand::eliminate_allocate_node(AllocateNode *alloc) {
1013   // If reallocation fails during deoptimization we'll pop all
1014   // interpreter frames for this compiled frame and that won't play
1015   // nice with JVMTI popframe.
1016   // We avoid this issue by eager reallocation when the popframe request
1017   // is received.
1018   if (!EliminateAllocations || !alloc->_is_non_escaping) {
1019     return false;
1020   }
1021   Node* klass = alloc->in(AllocateNode::KlassNode);
1022   const TypeKlassPtr* tklass = _igvn.type(klass)->is_klassptr();
1023   Node* res = alloc->result_cast();
1024   // Eliminate boxing allocations which are not used
1025   // regardless scalar replaceable status.
1026   bool boxing_alloc = C->eliminate_boxing() &&
1027                       tklass->isa_instklassptr() &&
1028                       tklass->is_instklassptr()->instance_klass()->is_box_klass();
1029   if (!alloc->_is_scalar_replaceable && (!boxing_alloc || (res != NULL))) {
1030     return false;
1031   }
1032 
1033   alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1034 
1035   GrowableArray <SafePointNode *> safepoints;
1036   if (!can_eliminate_allocation(alloc, safepoints)) {
1037     return false;
1038   }
1039 
1040   if (!alloc->_is_scalar_replaceable) {
1041     assert(res == NULL, "sanity");
1042     // We can only eliminate allocation if all debug info references
1043     // are already replaced with SafePointScalarObject because
1044     // we can't search for a fields value without instance_id.
1045     if (safepoints.length() > 0) {
1046       return false;
1047     }
1048   }
1049 
1050   if (!scalar_replacement(alloc, safepoints)) {
1051     return false;
1052   }
1053 
1054   CompileLog* log = C->log();
1055   if (log != NULL) {
1056     log->head("eliminate_allocation type='%d'",
1057               log->identify(tklass->exact_klass()));
1058     JVMState* p = alloc->jvms();
1059     while (p != NULL) {
1060       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1061       p = p->caller();
1062     }
1063     log->tail("eliminate_allocation");
1064   }
1065 
1066   process_users_of_allocation(alloc);
1067 
1068 #ifndef PRODUCT
1069   if (PrintEliminateAllocations) {
1070     if (alloc->is_AllocateArray())
1071       tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1072     else
1073       tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1074   }
1075 #endif
1076 
1077   return true;
1078 }
1079 
1080 bool PhaseMacroExpand::eliminate_boxing_node(CallStaticJavaNode *boxing) {
1081   // EA should remove all uses of non-escaping boxing node.
1082   if (!C->eliminate_boxing() || boxing->proj_out_or_null(TypeFunc::Parms) != NULL) {
1083     return false;
1084   }
1085 
1086   assert(boxing->result_cast() == NULL, "unexpected boxing node result");
1087 
1088   boxing->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1089 
1090   const TypeTuple* r = boxing->tf()->range();
1091   assert(r->cnt() > TypeFunc::Parms, "sanity");
1092   const TypeInstPtr* t = r->field_at(TypeFunc::Parms)->isa_instptr();
1093   assert(t != NULL, "sanity");
1094 
1095   CompileLog* log = C->log();
1096   if (log != NULL) {
1097     log->head("eliminate_boxing type='%d'",
1098               log->identify(t->instance_klass()));
1099     JVMState* p = boxing->jvms();
1100     while (p != NULL) {
1101       log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1102       p = p->caller();
1103     }
1104     log->tail("eliminate_boxing");
1105   }
1106 
1107   process_users_of_allocation(boxing);
1108 
1109 #ifndef PRODUCT
1110   if (PrintEliminateAllocations) {
1111     tty->print("++++ Eliminated: %d ", boxing->_idx);
1112     boxing->method()->print_short_name(tty);
1113     tty->cr();
1114   }
1115 #endif
1116 
1117   return true;
1118 }
1119 
1120 
1121 Node* PhaseMacroExpand::make_load(Node* ctl, Node* mem, Node* base, int offset, const Type* value_type, BasicType bt) {
1122   Node* adr = basic_plus_adr(base, offset);
1123   const TypePtr* adr_type = adr->bottom_type()->is_ptr();
1124   Node* value = LoadNode::make(_igvn, ctl, mem, adr, adr_type, value_type, bt, MemNode::unordered);
1125   transform_later(value);
1126   return value;
1127 }
1128 
1129 
1130 Node* PhaseMacroExpand::make_store(Node* ctl, Node* mem, Node* base, int offset, Node* value, BasicType bt) {
1131   Node* adr = basic_plus_adr(base, offset);
1132   mem = StoreNode::make(_igvn, ctl, mem, adr, NULL, value, bt, MemNode::unordered);
1133   transform_later(mem);
1134   return mem;
1135 }
1136 
1137 //=============================================================================
1138 //
1139 //                              A L L O C A T I O N
1140 //
1141 // Allocation attempts to be fast in the case of frequent small objects.
1142 // It breaks down like this:
1143 //
1144 // 1) Size in doublewords is computed.  This is a constant for objects and
1145 // variable for most arrays.  Doubleword units are used to avoid size
1146 // overflow of huge doubleword arrays.  We need doublewords in the end for
1147 // rounding.
1148 //
1149 // 2) Size is checked for being 'too large'.  Too-large allocations will go
1150 // the slow path into the VM.  The slow path can throw any required
1151 // exceptions, and does all the special checks for very large arrays.  The
1152 // size test can constant-fold away for objects.  For objects with
1153 // finalizers it constant-folds the otherway: you always go slow with
1154 // finalizers.
1155 //
1156 // 3) If NOT using TLABs, this is the contended loop-back point.
1157 // Load-Locked the heap top.  If using TLABs normal-load the heap top.
1158 //
1159 // 4) Check that heap top + size*8 < max.  If we fail go the slow ` route.
1160 // NOTE: "top+size*8" cannot wrap the 4Gig line!  Here's why: for largish
1161 // "size*8" we always enter the VM, where "largish" is a constant picked small
1162 // enough that there's always space between the eden max and 4Gig (old space is
1163 // there so it's quite large) and large enough that the cost of entering the VM
1164 // is dwarfed by the cost to initialize the space.
1165 //
1166 // 5) If NOT using TLABs, Store-Conditional the adjusted heap top back
1167 // down.  If contended, repeat at step 3.  If using TLABs normal-store
1168 // adjusted heap top back down; there is no contention.
1169 //
1170 // 6) If !ZeroTLAB then Bulk-clear the object/array.  Fill in klass & mark
1171 // fields.
1172 //
1173 // 7) Merge with the slow-path; cast the raw memory pointer to the correct
1174 // oop flavor.
1175 //
1176 //=============================================================================
1177 // FastAllocateSizeLimit value is in DOUBLEWORDS.
1178 // Allocations bigger than this always go the slow route.
1179 // This value must be small enough that allocation attempts that need to
1180 // trigger exceptions go the slow route.  Also, it must be small enough so
1181 // that heap_top + size_in_bytes does not wrap around the 4Gig limit.
1182 //=============================================================================j//
1183 // %%% Here is an old comment from parseHelper.cpp; is it outdated?
1184 // The allocator will coalesce int->oop copies away.  See comment in
1185 // coalesce.cpp about how this works.  It depends critically on the exact
1186 // code shape produced here, so if you are changing this code shape
1187 // make sure the GC info for the heap-top is correct in and around the
1188 // slow-path call.
1189 //
1190 
1191 void PhaseMacroExpand::expand_allocate_common(
1192             AllocateNode* alloc, // allocation node to be expanded
1193             Node* length,  // array length for an array allocation
1194             const TypeFunc* slow_call_type, // Type of slow call
1195             address slow_call_address,  // Address of slow call
1196             Node* valid_length_test // whether length is valid or not
1197     )
1198 {
1199   Node* ctrl = alloc->in(TypeFunc::Control);
1200   Node* mem  = alloc->in(TypeFunc::Memory);
1201   Node* i_o  = alloc->in(TypeFunc::I_O);
1202   Node* size_in_bytes     = alloc->in(AllocateNode::AllocSize);
1203   Node* klass_node        = alloc->in(AllocateNode::KlassNode);
1204   Node* initial_slow_test = alloc->in(AllocateNode::InitialTest);
1205   assert(ctrl != NULL, "must have control");
1206 
1207   // We need a Region and corresponding Phi's to merge the slow-path and fast-path results.
1208   // they will not be used if "always_slow" is set
1209   enum { slow_result_path = 1, fast_result_path = 2 };
1210   Node *result_region = NULL;
1211   Node *result_phi_rawmem = NULL;
1212   Node *result_phi_rawoop = NULL;
1213   Node *result_phi_i_o = NULL;
1214 
1215   // The initial slow comparison is a size check, the comparison
1216   // we want to do is a BoolTest::gt
1217   bool expand_fast_path = true;
1218   int tv = _igvn.find_int_con(initial_slow_test, -1);
1219   if (tv >= 0) {
1220     // InitialTest has constant result
1221     //   0 - can fit in TLAB
1222     //   1 - always too big or negative
1223     assert(tv <= 1, "0 or 1 if a constant");
1224     expand_fast_path = (tv == 0);
1225     initial_slow_test = NULL;
1226   } else {
1227     initial_slow_test = BoolNode::make_predicate(initial_slow_test, &_igvn);
1228   }
1229 
1230   if (!UseTLAB) {
1231     // Force slow-path allocation
1232     expand_fast_path = false;
1233     initial_slow_test = NULL;
1234   }
1235 
1236   bool allocation_has_use = (alloc->result_cast() != NULL);
1237   if (!allocation_has_use) {
1238     InitializeNode* init = alloc->initialization();
1239     if (init != NULL) {
1240       init->remove(&_igvn);
1241     }
1242     if (expand_fast_path && (initial_slow_test == NULL)) {
1243       // Remove allocation node and return.
1244       // Size is a non-negative constant -> no initial check needed -> directly to fast path.
1245       // Also, no usages -> empty fast path -> no fall out to slow path -> nothing left.
1246 #ifndef PRODUCT
1247       if (PrintEliminateAllocations) {
1248         tty->print("NotUsed ");
1249         Node* res = alloc->proj_out_or_null(TypeFunc::Parms);
1250         if (res != NULL) {
1251           res->dump();
1252         } else {
1253           alloc->dump();
1254         }
1255       }
1256 #endif
1257       yank_alloc_node(alloc);
1258       return;
1259     }
1260   }
1261 
1262   enum { too_big_or_final_path = 1, need_gc_path = 2 };
1263   Node *slow_region = NULL;
1264   Node *toobig_false = ctrl;
1265 
1266   // generate the initial test if necessary
1267   if (initial_slow_test != NULL ) {
1268     assert (expand_fast_path, "Only need test if there is a fast path");
1269     slow_region = new RegionNode(3);
1270 
1271     // Now make the initial failure test.  Usually a too-big test but
1272     // might be a TRUE for finalizers or a fancy class check for
1273     // newInstance0.
1274     IfNode *toobig_iff = new IfNode(ctrl, initial_slow_test, PROB_MIN, COUNT_UNKNOWN);
1275     transform_later(toobig_iff);
1276     // Plug the failing-too-big test into the slow-path region
1277     Node *toobig_true = new IfTrueNode( toobig_iff );
1278     transform_later(toobig_true);
1279     slow_region    ->init_req( too_big_or_final_path, toobig_true );
1280     toobig_false = new IfFalseNode( toobig_iff );
1281     transform_later(toobig_false);
1282   } else {
1283     // No initial test, just fall into next case
1284     assert(allocation_has_use || !expand_fast_path, "Should already have been handled");
1285     toobig_false = ctrl;
1286     debug_only(slow_region = NodeSentinel);
1287   }
1288 
1289   // If we are here there are several possibilities
1290   // - expand_fast_path is false - then only a slow path is expanded. That's it.
1291   // no_initial_check means a constant allocation.
1292   // - If check always evaluates to false -> expand_fast_path is false (see above)
1293   // - If check always evaluates to true -> directly into fast path (but may bailout to slowpath)
1294   // if !allocation_has_use the fast path is empty
1295   // if !allocation_has_use && no_initial_check
1296   // - Then there are no fastpath that can fall out to slowpath -> no allocation code at all.
1297   //   removed by yank_alloc_node above.
1298 
1299   Node *slow_mem = mem;  // save the current memory state for slow path
1300   // generate the fast allocation code unless we know that the initial test will always go slow
1301   if (expand_fast_path) {
1302     // Fast path modifies only raw memory.
1303     if (mem->is_MergeMem()) {
1304       mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1305     }
1306 
1307     // allocate the Region and Phi nodes for the result
1308     result_region = new RegionNode(3);
1309     result_phi_rawmem = new PhiNode(result_region, Type::MEMORY, TypeRawPtr::BOTTOM);
1310     result_phi_i_o    = new PhiNode(result_region, Type::ABIO); // I/O is used for Prefetch
1311 
1312     // Grab regular I/O before optional prefetch may change it.
1313     // Slow-path does no I/O so just set it to the original I/O.
1314     result_phi_i_o->init_req(slow_result_path, i_o);
1315 
1316     // Name successful fast-path variables
1317     Node* fast_oop_ctrl;
1318     Node* fast_oop_rawmem;
1319     if (allocation_has_use) {
1320       Node* needgc_ctrl = NULL;
1321       result_phi_rawoop = new PhiNode(result_region, TypeRawPtr::BOTTOM);
1322 
1323       intx prefetch_lines = length != NULL ? AllocatePrefetchLines : AllocateInstancePrefetchLines;
1324       BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1325       Node* fast_oop = bs->obj_allocate(this, mem, toobig_false, size_in_bytes, i_o, needgc_ctrl,
1326                                         fast_oop_ctrl, fast_oop_rawmem,
1327                                         prefetch_lines);
1328 
1329       if (initial_slow_test != NULL) {
1330         // This completes all paths into the slow merge point
1331         slow_region->init_req(need_gc_path, needgc_ctrl);
1332         transform_later(slow_region);
1333       } else {
1334         // No initial slow path needed!
1335         // Just fall from the need-GC path straight into the VM call.
1336         slow_region = needgc_ctrl;
1337       }
1338 
1339       InitializeNode* init = alloc->initialization();
1340       fast_oop_rawmem = initialize_object(alloc,
1341                                           fast_oop_ctrl, fast_oop_rawmem, fast_oop,
1342                                           klass_node, length, size_in_bytes);
1343       expand_initialize_membar(alloc, init, fast_oop_ctrl, fast_oop_rawmem);
1344       expand_dtrace_alloc_probe(alloc, fast_oop, fast_oop_ctrl, fast_oop_rawmem);
1345 
1346       result_phi_rawoop->init_req(fast_result_path, fast_oop);
1347     } else {
1348       assert (initial_slow_test != NULL, "sanity");
1349       fast_oop_ctrl   = toobig_false;
1350       fast_oop_rawmem = mem;
1351       transform_later(slow_region);
1352     }
1353 
1354     // Plug in the successful fast-path into the result merge point
1355     result_region    ->init_req(fast_result_path, fast_oop_ctrl);
1356     result_phi_i_o   ->init_req(fast_result_path, i_o);
1357     result_phi_rawmem->init_req(fast_result_path, fast_oop_rawmem);
1358   } else {
1359     slow_region = ctrl;
1360     result_phi_i_o = i_o; // Rename it to use in the following code.
1361   }
1362 
1363   // Generate slow-path call
1364   CallNode *call = new CallStaticJavaNode(slow_call_type, slow_call_address,
1365                                OptoRuntime::stub_name(slow_call_address),
1366                                TypePtr::BOTTOM);
1367   call->init_req(TypeFunc::Control,   slow_region);
1368   call->init_req(TypeFunc::I_O,       top());    // does no i/o
1369   call->init_req(TypeFunc::Memory,    slow_mem); // may gc ptrs
1370   call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1371   call->init_req(TypeFunc::FramePtr,  alloc->in(TypeFunc::FramePtr));
1372 
1373   call->init_req(TypeFunc::Parms+0, klass_node);
1374   if (length != NULL) {
1375     call->init_req(TypeFunc::Parms+1, length);
1376   }
1377 
1378   // Copy debug information and adjust JVMState information, then replace
1379   // allocate node with the call
1380   call->copy_call_debug_info(&_igvn, alloc);
1381   // For array allocations, copy the valid length check to the call node so Compile::final_graph_reshaping() can verify
1382   // that the call has the expected number of CatchProj nodes (in case the allocation always fails and the fallthrough
1383   // path dies).
1384   if (valid_length_test != NULL) {
1385     call->add_req(valid_length_test);
1386   }
1387   if (expand_fast_path) {
1388     call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
1389   } else {
1390     // Hook i_o projection to avoid its elimination during allocation
1391     // replacement (when only a slow call is generated).
1392     call->set_req(TypeFunc::I_O, result_phi_i_o);
1393   }
1394   _igvn.replace_node(alloc, call);
1395   transform_later(call);
1396 
1397   // Identify the output projections from the allocate node and
1398   // adjust any references to them.
1399   // The control and io projections look like:
1400   //
1401   //        v---Proj(ctrl) <-----+   v---CatchProj(ctrl)
1402   //  Allocate                   Catch
1403   //        ^---Proj(io) <-------+   ^---CatchProj(io)
1404   //
1405   //  We are interested in the CatchProj nodes.
1406   //
1407   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1408 
1409   // An allocate node has separate memory projections for the uses on
1410   // the control and i_o paths. Replace the control memory projection with
1411   // result_phi_rawmem (unless we are only generating a slow call when
1412   // both memory projections are combined)
1413   if (expand_fast_path && _callprojs.fallthrough_memproj != NULL) {
1414     migrate_outs(_callprojs.fallthrough_memproj, result_phi_rawmem);
1415   }
1416   // Now change uses of catchall_memproj to use fallthrough_memproj and delete
1417   // catchall_memproj so we end up with a call that has only 1 memory projection.
1418   if (_callprojs.catchall_memproj != NULL ) {
1419     if (_callprojs.fallthrough_memproj == NULL) {
1420       _callprojs.fallthrough_memproj = new ProjNode(call, TypeFunc::Memory);
1421       transform_later(_callprojs.fallthrough_memproj);
1422     }
1423     migrate_outs(_callprojs.catchall_memproj, _callprojs.fallthrough_memproj);
1424     _igvn.remove_dead_node(_callprojs.catchall_memproj);
1425   }
1426 
1427   // An allocate node has separate i_o projections for the uses on the control
1428   // and i_o paths. Always replace the control i_o projection with result i_o
1429   // otherwise incoming i_o become dead when only a slow call is generated
1430   // (it is different from memory projections where both projections are
1431   // combined in such case).
1432   if (_callprojs.fallthrough_ioproj != NULL) {
1433     migrate_outs(_callprojs.fallthrough_ioproj, result_phi_i_o);
1434   }
1435   // Now change uses of catchall_ioproj to use fallthrough_ioproj and delete
1436   // catchall_ioproj so we end up with a call that has only 1 i_o projection.
1437   if (_callprojs.catchall_ioproj != NULL ) {
1438     if (_callprojs.fallthrough_ioproj == NULL) {
1439       _callprojs.fallthrough_ioproj = new ProjNode(call, TypeFunc::I_O);
1440       transform_later(_callprojs.fallthrough_ioproj);
1441     }
1442     migrate_outs(_callprojs.catchall_ioproj, _callprojs.fallthrough_ioproj);
1443     _igvn.remove_dead_node(_callprojs.catchall_ioproj);
1444   }
1445 
1446   // if we generated only a slow call, we are done
1447   if (!expand_fast_path) {
1448     // Now we can unhook i_o.
1449     if (result_phi_i_o->outcnt() > 1) {
1450       call->set_req(TypeFunc::I_O, top());
1451     } else {
1452       assert(result_phi_i_o->unique_ctrl_out() == call, "sanity");
1453       // Case of new array with negative size known during compilation.
1454       // AllocateArrayNode::Ideal() optimization disconnect unreachable
1455       // following code since call to runtime will throw exception.
1456       // As result there will be no users of i_o after the call.
1457       // Leave i_o attached to this call to avoid problems in preceding graph.
1458     }
1459     return;
1460   }
1461 
1462   if (_callprojs.fallthrough_catchproj != NULL) {
1463     ctrl = _callprojs.fallthrough_catchproj->clone();
1464     transform_later(ctrl);
1465     _igvn.replace_node(_callprojs.fallthrough_catchproj, result_region);
1466   } else {
1467     ctrl = top();
1468   }
1469   Node *slow_result;
1470   if (_callprojs.resproj == NULL) {
1471     // no uses of the allocation result
1472     slow_result = top();
1473   } else {
1474     slow_result = _callprojs.resproj->clone();
1475     transform_later(slow_result);
1476     _igvn.replace_node(_callprojs.resproj, result_phi_rawoop);
1477   }
1478 
1479   // Plug slow-path into result merge point
1480   result_region->init_req( slow_result_path, ctrl);
1481   transform_later(result_region);
1482   if (allocation_has_use) {
1483     result_phi_rawoop->init_req(slow_result_path, slow_result);
1484     transform_later(result_phi_rawoop);
1485   }
1486   result_phi_rawmem->init_req(slow_result_path, _callprojs.fallthrough_memproj);
1487   transform_later(result_phi_rawmem);
1488   transform_later(result_phi_i_o);
1489   // This completes all paths into the result merge point
1490 }
1491 
1492 // Remove alloc node that has no uses.
1493 void PhaseMacroExpand::yank_alloc_node(AllocateNode* alloc) {
1494   Node* ctrl = alloc->in(TypeFunc::Control);
1495   Node* mem  = alloc->in(TypeFunc::Memory);
1496   Node* i_o  = alloc->in(TypeFunc::I_O);
1497 
1498   alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1499   if (_callprojs.resproj != NULL) {
1500     for (DUIterator_Fast imax, i = _callprojs.resproj->fast_outs(imax); i < imax; i++) {
1501       Node* use = _callprojs.resproj->fast_out(i);
1502       use->isa_MemBar()->remove(&_igvn);
1503       --imax;
1504       --i; // back up iterator
1505     }
1506     assert(_callprojs.resproj->outcnt() == 0, "all uses must be deleted");
1507     _igvn.remove_dead_node(_callprojs.resproj);
1508   }
1509   if (_callprojs.fallthrough_catchproj != NULL) {
1510     migrate_outs(_callprojs.fallthrough_catchproj, ctrl);
1511     _igvn.remove_dead_node(_callprojs.fallthrough_catchproj);
1512   }
1513   if (_callprojs.catchall_catchproj != NULL) {
1514     _igvn.rehash_node_delayed(_callprojs.catchall_catchproj);
1515     _callprojs.catchall_catchproj->set_req(0, top());
1516   }
1517   if (_callprojs.fallthrough_proj != NULL) {
1518     Node* catchnode = _callprojs.fallthrough_proj->unique_ctrl_out();
1519     _igvn.remove_dead_node(catchnode);
1520     _igvn.remove_dead_node(_callprojs.fallthrough_proj);
1521   }
1522   if (_callprojs.fallthrough_memproj != NULL) {
1523     migrate_outs(_callprojs.fallthrough_memproj, mem);
1524     _igvn.remove_dead_node(_callprojs.fallthrough_memproj);
1525   }
1526   if (_callprojs.fallthrough_ioproj != NULL) {
1527     migrate_outs(_callprojs.fallthrough_ioproj, i_o);
1528     _igvn.remove_dead_node(_callprojs.fallthrough_ioproj);
1529   }
1530   if (_callprojs.catchall_memproj != NULL) {
1531     _igvn.rehash_node_delayed(_callprojs.catchall_memproj);
1532     _callprojs.catchall_memproj->set_req(0, top());
1533   }
1534   if (_callprojs.catchall_ioproj != NULL) {
1535     _igvn.rehash_node_delayed(_callprojs.catchall_ioproj);
1536     _callprojs.catchall_ioproj->set_req(0, top());
1537   }
1538 #ifndef PRODUCT
1539   if (PrintEliminateAllocations) {
1540     if (alloc->is_AllocateArray()) {
1541       tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1542     } else {
1543       tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1544     }
1545   }
1546 #endif
1547   _igvn.remove_dead_node(alloc);
1548 }
1549 
1550 void PhaseMacroExpand::expand_initialize_membar(AllocateNode* alloc, InitializeNode* init,
1551                                                 Node*& fast_oop_ctrl, Node*& fast_oop_rawmem) {
1552   // If initialization is performed by an array copy, any required
1553   // MemBarStoreStore was already added. If the object does not
1554   // escape no need for a MemBarStoreStore. If the object does not
1555   // escape in its initializer and memory barrier (MemBarStoreStore or
1556   // stronger) is already added at exit of initializer, also no need
1557   // for a MemBarStoreStore. Otherwise we need a MemBarStoreStore
1558   // so that stores that initialize this object can't be reordered
1559   // with a subsequent store that makes this object accessible by
1560   // other threads.
1561   // Other threads include java threads and JVM internal threads
1562   // (for example concurrent GC threads). Current concurrent GC
1563   // implementation: G1 will not scan newly created object,
1564   // so it's safe to skip storestore barrier when allocation does
1565   // not escape.
1566   if (!alloc->does_not_escape_thread() &&
1567     !alloc->is_allocation_MemBar_redundant() &&
1568     (init == NULL || !init->is_complete_with_arraycopy())) {
1569     if (init == NULL || init->req() < InitializeNode::RawStores) {
1570       // No InitializeNode or no stores captured by zeroing
1571       // elimination. Simply add the MemBarStoreStore after object
1572       // initialization.
1573       MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
1574       transform_later(mb);
1575 
1576       mb->init_req(TypeFunc::Memory, fast_oop_rawmem);
1577       mb->init_req(TypeFunc::Control, fast_oop_ctrl);
1578       fast_oop_ctrl = new ProjNode(mb, TypeFunc::Control);
1579       transform_later(fast_oop_ctrl);
1580       fast_oop_rawmem = new ProjNode(mb, TypeFunc::Memory);
1581       transform_later(fast_oop_rawmem);
1582     } else {
1583       // Add the MemBarStoreStore after the InitializeNode so that
1584       // all stores performing the initialization that were moved
1585       // before the InitializeNode happen before the storestore
1586       // barrier.
1587 
1588       Node* init_ctrl = init->proj_out_or_null(TypeFunc::Control);
1589       Node* init_mem = init->proj_out_or_null(TypeFunc::Memory);
1590 
1591       MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
1592       transform_later(mb);
1593 
1594       Node* ctrl = new ProjNode(init, TypeFunc::Control);
1595       transform_later(ctrl);
1596       Node* mem = new ProjNode(init, TypeFunc::Memory);
1597       transform_later(mem);
1598 
1599       // The MemBarStoreStore depends on control and memory coming
1600       // from the InitializeNode
1601       mb->init_req(TypeFunc::Memory, mem);
1602       mb->init_req(TypeFunc::Control, ctrl);
1603 
1604       ctrl = new ProjNode(mb, TypeFunc::Control);
1605       transform_later(ctrl);
1606       mem = new ProjNode(mb, TypeFunc::Memory);
1607       transform_later(mem);
1608 
1609       // All nodes that depended on the InitializeNode for control
1610       // and memory must now depend on the MemBarNode that itself
1611       // depends on the InitializeNode
1612       if (init_ctrl != NULL) {
1613         _igvn.replace_node(init_ctrl, ctrl);
1614       }
1615       if (init_mem != NULL) {
1616         _igvn.replace_node(init_mem, mem);
1617       }
1618     }
1619   }
1620 }
1621 
1622 void PhaseMacroExpand::expand_dtrace_alloc_probe(AllocateNode* alloc, Node* oop,
1623                                                 Node*& ctrl, Node*& rawmem) {
1624   if (C->env()->dtrace_alloc_probes()) {
1625     // Slow-path call
1626     int size = TypeFunc::Parms + 2;
1627     CallLeafNode *call = new CallLeafNode(OptoRuntime::dtrace_object_alloc_Type(),
1628                                           CAST_FROM_FN_PTR(address,
1629                                           static_cast<int (*)(Thread*, oopDesc*)>(SharedRuntime::dtrace_object_alloc)),
1630                                           "dtrace_object_alloc",
1631                                           TypeRawPtr::BOTTOM);
1632 
1633     // Get base of thread-local storage area
1634     Node* thread = new ThreadLocalNode();
1635     transform_later(thread);
1636 
1637     call->init_req(TypeFunc::Parms + 0, thread);
1638     call->init_req(TypeFunc::Parms + 1, oop);
1639     call->init_req(TypeFunc::Control, ctrl);
1640     call->init_req(TypeFunc::I_O    , top()); // does no i/o
1641     call->init_req(TypeFunc::Memory , rawmem);
1642     call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1643     call->init_req(TypeFunc::FramePtr, alloc->in(TypeFunc::FramePtr));
1644     transform_later(call);
1645     ctrl = new ProjNode(call, TypeFunc::Control);
1646     transform_later(ctrl);
1647     rawmem = new ProjNode(call, TypeFunc::Memory);
1648     transform_later(rawmem);
1649   }
1650 }
1651 
1652 // Helper for PhaseMacroExpand::expand_allocate_common.
1653 // Initializes the newly-allocated storage.
1654 Node*
1655 PhaseMacroExpand::initialize_object(AllocateNode* alloc,
1656                                     Node* control, Node* rawmem, Node* object,
1657                                     Node* klass_node, Node* length,
1658                                     Node* size_in_bytes) {
1659   InitializeNode* init = alloc->initialization();
1660   // Store the klass & mark bits
1661   Node* mark_node = alloc->make_ideal_mark(&_igvn, object, control, rawmem);
1662   if (!mark_node->is_Con()) {
1663     transform_later(mark_node);
1664   }
1665   rawmem = make_store(control, rawmem, object, oopDesc::mark_offset_in_bytes(), mark_node, TypeX_X->basic_type());
1666 

1667   rawmem = make_store(control, rawmem, object, oopDesc::klass_offset_in_bytes(), klass_node, T_METADATA);

1668   int header_size = alloc->minimum_header_size();  // conservatively small
1669 
1670   // Array length
1671   if (length != NULL) {         // Arrays need length field
1672     rawmem = make_store(control, rawmem, object, arrayOopDesc::length_offset_in_bytes(), length, T_INT);
1673     // conservatively small header size:
1674     header_size = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1675     if (_igvn.type(klass_node)->isa_aryklassptr()) {   // we know the exact header size in most cases:
1676       BasicType elem = _igvn.type(klass_node)->is_klassptr()->as_instance_type()->isa_aryptr()->elem()->array_element_basic_type();
1677       if (is_reference_type(elem, true)) {
1678         elem = T_OBJECT;
1679       }
1680       header_size = Klass::layout_helper_header_size(Klass::array_layout_helper(elem));
1681     }
1682   }
1683 
1684   // Clear the object body, if necessary.
1685   if (init == NULL) {
1686     // The init has somehow disappeared; be cautious and clear everything.
1687     //
1688     // This can happen if a node is allocated but an uncommon trap occurs
1689     // immediately.  In this case, the Initialize gets associated with the
1690     // trap, and may be placed in a different (outer) loop, if the Allocate
1691     // is in a loop.  If (this is rare) the inner loop gets unrolled, then
1692     // there can be two Allocates to one Initialize.  The answer in all these
1693     // edge cases is safety first.  It is always safe to clear immediately
1694     // within an Allocate, and then (maybe or maybe not) clear some more later.
1695     if (!(UseTLAB && ZeroTLAB)) {
1696       rawmem = ClearArrayNode::clear_memory(control, rawmem, object,
1697                                             header_size, size_in_bytes,
1698                                             &_igvn);
1699     }
1700   } else {
1701     if (!init->is_complete()) {
1702       // Try to win by zeroing only what the init does not store.
1703       // We can also try to do some peephole optimizations,
1704       // such as combining some adjacent subword stores.
1705       rawmem = init->complete_stores(control, rawmem, object,
1706                                      header_size, size_in_bytes, &_igvn);
1707     }
1708     // We have no more use for this link, since the AllocateNode goes away:
1709     init->set_req(InitializeNode::RawAddress, top());
1710     // (If we keep the link, it just confuses the register allocator,
1711     // who thinks he sees a real use of the address by the membar.)
1712   }
1713 
1714   return rawmem;
1715 }
1716 
1717 // Generate prefetch instructions for next allocations.
1718 Node* PhaseMacroExpand::prefetch_allocation(Node* i_o, Node*& needgc_false,
1719                                         Node*& contended_phi_rawmem,
1720                                         Node* old_eden_top, Node* new_eden_top,
1721                                         intx lines) {
1722    enum { fall_in_path = 1, pf_path = 2 };
1723    if( UseTLAB && AllocatePrefetchStyle == 2 ) {
1724       // Generate prefetch allocation with watermark check.
1725       // As an allocation hits the watermark, we will prefetch starting
1726       // at a "distance" away from watermark.
1727 
1728       Node *pf_region = new RegionNode(3);
1729       Node *pf_phi_rawmem = new PhiNode( pf_region, Type::MEMORY,
1730                                                 TypeRawPtr::BOTTOM );
1731       // I/O is used for Prefetch
1732       Node *pf_phi_abio = new PhiNode( pf_region, Type::ABIO );
1733 
1734       Node *thread = new ThreadLocalNode();
1735       transform_later(thread);
1736 
1737       Node *eden_pf_adr = new AddPNode( top()/*not oop*/, thread,
1738                    _igvn.MakeConX(in_bytes(JavaThread::tlab_pf_top_offset())) );
1739       transform_later(eden_pf_adr);
1740 
1741       Node *old_pf_wm = new LoadPNode(needgc_false,
1742                                    contended_phi_rawmem, eden_pf_adr,
1743                                    TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM,
1744                                    MemNode::unordered);
1745       transform_later(old_pf_wm);
1746 
1747       // check against new_eden_top
1748       Node *need_pf_cmp = new CmpPNode( new_eden_top, old_pf_wm );
1749       transform_later(need_pf_cmp);
1750       Node *need_pf_bol = new BoolNode( need_pf_cmp, BoolTest::ge );
1751       transform_later(need_pf_bol);
1752       IfNode *need_pf_iff = new IfNode( needgc_false, need_pf_bol,
1753                                        PROB_UNLIKELY_MAG(4), COUNT_UNKNOWN );
1754       transform_later(need_pf_iff);
1755 
1756       // true node, add prefetchdistance
1757       Node *need_pf_true = new IfTrueNode( need_pf_iff );
1758       transform_later(need_pf_true);
1759 
1760       Node *need_pf_false = new IfFalseNode( need_pf_iff );
1761       transform_later(need_pf_false);
1762 
1763       Node *new_pf_wmt = new AddPNode( top(), old_pf_wm,
1764                                     _igvn.MakeConX(AllocatePrefetchDistance) );
1765       transform_later(new_pf_wmt );
1766       new_pf_wmt->set_req(0, need_pf_true);
1767 
1768       Node *store_new_wmt = new StorePNode(need_pf_true,
1769                                        contended_phi_rawmem, eden_pf_adr,
1770                                        TypeRawPtr::BOTTOM, new_pf_wmt,
1771                                        MemNode::unordered);
1772       transform_later(store_new_wmt);
1773 
1774       // adding prefetches
1775       pf_phi_abio->init_req( fall_in_path, i_o );
1776 
1777       Node *prefetch_adr;
1778       Node *prefetch;
1779       uint step_size = AllocatePrefetchStepSize;
1780       uint distance = 0;
1781 
1782       for ( intx i = 0; i < lines; i++ ) {
1783         prefetch_adr = new AddPNode( old_pf_wm, new_pf_wmt,
1784                                             _igvn.MakeConX(distance) );
1785         transform_later(prefetch_adr);
1786         prefetch = new PrefetchAllocationNode( i_o, prefetch_adr );
1787         transform_later(prefetch);
1788         distance += step_size;
1789         i_o = prefetch;
1790       }
1791       pf_phi_abio->set_req( pf_path, i_o );
1792 
1793       pf_region->init_req( fall_in_path, need_pf_false );
1794       pf_region->init_req( pf_path, need_pf_true );
1795 
1796       pf_phi_rawmem->init_req( fall_in_path, contended_phi_rawmem );
1797       pf_phi_rawmem->init_req( pf_path, store_new_wmt );
1798 
1799       transform_later(pf_region);
1800       transform_later(pf_phi_rawmem);
1801       transform_later(pf_phi_abio);
1802 
1803       needgc_false = pf_region;
1804       contended_phi_rawmem = pf_phi_rawmem;
1805       i_o = pf_phi_abio;
1806    } else if( UseTLAB && AllocatePrefetchStyle == 3 ) {
1807       // Insert a prefetch instruction for each allocation.
1808       // This code is used to generate 1 prefetch instruction per cache line.
1809 
1810       // Generate several prefetch instructions.
1811       uint step_size = AllocatePrefetchStepSize;
1812       uint distance = AllocatePrefetchDistance;
1813 
1814       // Next cache address.
1815       Node *cache_adr = new AddPNode(old_eden_top, old_eden_top,
1816                                      _igvn.MakeConX(step_size + distance));
1817       transform_later(cache_adr);
1818       cache_adr = new CastP2XNode(needgc_false, cache_adr);
1819       transform_later(cache_adr);
1820       // Address is aligned to execute prefetch to the beginning of cache line size
1821       // (it is important when BIS instruction is used on SPARC as prefetch).
1822       Node* mask = _igvn.MakeConX(~(intptr_t)(step_size-1));
1823       cache_adr = new AndXNode(cache_adr, mask);
1824       transform_later(cache_adr);
1825       cache_adr = new CastX2PNode(cache_adr);
1826       transform_later(cache_adr);
1827 
1828       // Prefetch
1829       Node *prefetch = new PrefetchAllocationNode( contended_phi_rawmem, cache_adr );
1830       prefetch->set_req(0, needgc_false);
1831       transform_later(prefetch);
1832       contended_phi_rawmem = prefetch;
1833       Node *prefetch_adr;
1834       distance = step_size;
1835       for ( intx i = 1; i < lines; i++ ) {
1836         prefetch_adr = new AddPNode( cache_adr, cache_adr,
1837                                             _igvn.MakeConX(distance) );
1838         transform_later(prefetch_adr);
1839         prefetch = new PrefetchAllocationNode( contended_phi_rawmem, prefetch_adr );
1840         transform_later(prefetch);
1841         distance += step_size;
1842         contended_phi_rawmem = prefetch;
1843       }
1844    } else if( AllocatePrefetchStyle > 0 ) {
1845       // Insert a prefetch for each allocation only on the fast-path
1846       Node *prefetch_adr;
1847       Node *prefetch;
1848       // Generate several prefetch instructions.
1849       uint step_size = AllocatePrefetchStepSize;
1850       uint distance = AllocatePrefetchDistance;
1851       for ( intx i = 0; i < lines; i++ ) {
1852         prefetch_adr = new AddPNode( old_eden_top, new_eden_top,
1853                                             _igvn.MakeConX(distance) );
1854         transform_later(prefetch_adr);
1855         prefetch = new PrefetchAllocationNode( i_o, prefetch_adr );
1856         // Do not let it float too high, since if eden_top == eden_end,
1857         // both might be null.
1858         if( i == 0 ) { // Set control for first prefetch, next follows it
1859           prefetch->init_req(0, needgc_false);
1860         }
1861         transform_later(prefetch);
1862         distance += step_size;
1863         i_o = prefetch;
1864       }
1865    }
1866    return i_o;
1867 }
1868 
1869 
1870 void PhaseMacroExpand::expand_allocate(AllocateNode *alloc) {
1871   expand_allocate_common(alloc, NULL,
1872                          OptoRuntime::new_instance_Type(),
1873                          OptoRuntime::new_instance_Java(), NULL);
1874 }
1875 
1876 void PhaseMacroExpand::expand_allocate_array(AllocateArrayNode *alloc) {
1877   Node* length = alloc->in(AllocateNode::ALength);
1878   Node* valid_length_test = alloc->in(AllocateNode::ValidLengthTest);
1879   InitializeNode* init = alloc->initialization();
1880   Node* klass_node = alloc->in(AllocateNode::KlassNode);
1881   const TypeAryKlassPtr* ary_klass_t = _igvn.type(klass_node)->isa_aryklassptr();
1882   address slow_call_address;  // Address of slow call
1883   if (init != NULL && init->is_complete_with_arraycopy() &&
1884       ary_klass_t && ary_klass_t->elem()->isa_klassptr() == NULL) {
1885     // Don't zero type array during slow allocation in VM since
1886     // it will be initialized later by arraycopy in compiled code.
1887     slow_call_address = OptoRuntime::new_array_nozero_Java();
1888   } else {
1889     slow_call_address = OptoRuntime::new_array_Java();
1890   }
1891   expand_allocate_common(alloc, length,
1892                          OptoRuntime::new_array_Type(),
1893                          slow_call_address, valid_length_test);
1894 }
1895 
1896 //-------------------mark_eliminated_box----------------------------------
1897 //
1898 // During EA obj may point to several objects but after few ideal graph
1899 // transformations (CCP) it may point to only one non escaping object
1900 // (but still using phi), corresponding locks and unlocks will be marked
1901 // for elimination. Later obj could be replaced with a new node (new phi)
1902 // and which does not have escape information. And later after some graph
1903 // reshape other locks and unlocks (which were not marked for elimination
1904 // before) are connected to this new obj (phi) but they still will not be
1905 // marked for elimination since new obj has no escape information.
1906 // Mark all associated (same box and obj) lock and unlock nodes for
1907 // elimination if some of them marked already.
1908 void PhaseMacroExpand::mark_eliminated_box(Node* oldbox, Node* obj) {
1909   if (oldbox->as_BoxLock()->is_eliminated()) {
1910     return; // This BoxLock node was processed already.
1911   }
1912   // New implementation (EliminateNestedLocks) has separate BoxLock
1913   // node for each locked region so mark all associated locks/unlocks as
1914   // eliminated even if different objects are referenced in one locked region
1915   // (for example, OSR compilation of nested loop inside locked scope).
1916   if (EliminateNestedLocks ||
1917       oldbox->as_BoxLock()->is_simple_lock_region(NULL, obj, NULL)) {
1918     // Box is used only in one lock region. Mark this box as eliminated.
1919     _igvn.hash_delete(oldbox);
1920     oldbox->as_BoxLock()->set_eliminated(); // This changes box's hash value
1921      _igvn.hash_insert(oldbox);
1922 
1923     for (uint i = 0; i < oldbox->outcnt(); i++) {
1924       Node* u = oldbox->raw_out(i);
1925       if (u->is_AbstractLock() && !u->as_AbstractLock()->is_non_esc_obj()) {
1926         AbstractLockNode* alock = u->as_AbstractLock();
1927         // Check lock's box since box could be referenced by Lock's debug info.
1928         if (alock->box_node() == oldbox) {
1929           // Mark eliminated all related locks and unlocks.
1930 #ifdef ASSERT
1931           alock->log_lock_optimization(C, "eliminate_lock_set_non_esc4");
1932 #endif
1933           alock->set_non_esc_obj();
1934         }
1935       }
1936     }
1937     return;
1938   }
1939 
1940   // Create new "eliminated" BoxLock node and use it in monitor debug info
1941   // instead of oldbox for the same object.
1942   BoxLockNode* newbox = oldbox->clone()->as_BoxLock();
1943 
1944   // Note: BoxLock node is marked eliminated only here and it is used
1945   // to indicate that all associated lock and unlock nodes are marked
1946   // for elimination.
1947   newbox->set_eliminated();
1948   transform_later(newbox);
1949 
1950   // Replace old box node with new box for all users of the same object.
1951   for (uint i = 0; i < oldbox->outcnt();) {
1952     bool next_edge = true;
1953 
1954     Node* u = oldbox->raw_out(i);
1955     if (u->is_AbstractLock()) {
1956       AbstractLockNode* alock = u->as_AbstractLock();
1957       if (alock->box_node() == oldbox && alock->obj_node()->eqv_uncast(obj)) {
1958         // Replace Box and mark eliminated all related locks and unlocks.
1959 #ifdef ASSERT
1960         alock->log_lock_optimization(C, "eliminate_lock_set_non_esc5");
1961 #endif
1962         alock->set_non_esc_obj();
1963         _igvn.rehash_node_delayed(alock);
1964         alock->set_box_node(newbox);
1965         next_edge = false;
1966       }
1967     }
1968     if (u->is_FastLock() && u->as_FastLock()->obj_node()->eqv_uncast(obj)) {
1969       FastLockNode* flock = u->as_FastLock();
1970       assert(flock->box_node() == oldbox, "sanity");
1971       _igvn.rehash_node_delayed(flock);
1972       flock->set_box_node(newbox);
1973       next_edge = false;
1974     }
1975 
1976     // Replace old box in monitor debug info.
1977     if (u->is_SafePoint() && u->as_SafePoint()->jvms()) {
1978       SafePointNode* sfn = u->as_SafePoint();
1979       JVMState* youngest_jvms = sfn->jvms();
1980       int max_depth = youngest_jvms->depth();
1981       for (int depth = 1; depth <= max_depth; depth++) {
1982         JVMState* jvms = youngest_jvms->of_depth(depth);
1983         int num_mon  = jvms->nof_monitors();
1984         // Loop over monitors
1985         for (int idx = 0; idx < num_mon; idx++) {
1986           Node* obj_node = sfn->monitor_obj(jvms, idx);
1987           Node* box_node = sfn->monitor_box(jvms, idx);
1988           if (box_node == oldbox && obj_node->eqv_uncast(obj)) {
1989             int j = jvms->monitor_box_offset(idx);
1990             _igvn.replace_input_of(u, j, newbox);
1991             next_edge = false;
1992           }
1993         }
1994       }
1995     }
1996     if (next_edge) i++;
1997   }
1998 }
1999 
2000 //-----------------------mark_eliminated_locking_nodes-----------------------
2001 void PhaseMacroExpand::mark_eliminated_locking_nodes(AbstractLockNode *alock) {
2002   if (EliminateNestedLocks) {
2003     if (alock->is_nested()) {
2004        assert(alock->box_node()->as_BoxLock()->is_eliminated(), "sanity");
2005        return;
2006     } else if (!alock->is_non_esc_obj()) { // Not eliminated or coarsened
2007       // Only Lock node has JVMState needed here.
2008       // Not that preceding claim is documented anywhere else.
2009       if (alock->jvms() != NULL) {
2010         if (alock->as_Lock()->is_nested_lock_region()) {
2011           // Mark eliminated related nested locks and unlocks.
2012           Node* obj = alock->obj_node();
2013           BoxLockNode* box_node = alock->box_node()->as_BoxLock();
2014           assert(!box_node->is_eliminated(), "should not be marked yet");
2015           // Note: BoxLock node is marked eliminated only here
2016           // and it is used to indicate that all associated lock
2017           // and unlock nodes are marked for elimination.
2018           box_node->set_eliminated(); // Box's hash is always NO_HASH here
2019           for (uint i = 0; i < box_node->outcnt(); i++) {
2020             Node* u = box_node->raw_out(i);
2021             if (u->is_AbstractLock()) {
2022               alock = u->as_AbstractLock();
2023               if (alock->box_node() == box_node) {
2024                 // Verify that this Box is referenced only by related locks.
2025                 assert(alock->obj_node()->eqv_uncast(obj), "");
2026                 // Mark all related locks and unlocks.
2027 #ifdef ASSERT
2028                 alock->log_lock_optimization(C, "eliminate_lock_set_nested");
2029 #endif
2030                 alock->set_nested();
2031               }
2032             }
2033           }
2034         } else {
2035 #ifdef ASSERT
2036           alock->log_lock_optimization(C, "eliminate_lock_NOT_nested_lock_region");
2037           if (C->log() != NULL)
2038             alock->as_Lock()->is_nested_lock_region(C); // rerun for debugging output
2039 #endif
2040         }
2041       }
2042       return;
2043     }
2044     // Process locks for non escaping object
2045     assert(alock->is_non_esc_obj(), "");
2046   } // EliminateNestedLocks
2047 
2048   if (alock->is_non_esc_obj()) { // Lock is used for non escaping object
2049     // Look for all locks of this object and mark them and
2050     // corresponding BoxLock nodes as eliminated.
2051     Node* obj = alock->obj_node();
2052     for (uint j = 0; j < obj->outcnt(); j++) {
2053       Node* o = obj->raw_out(j);
2054       if (o->is_AbstractLock() &&
2055           o->as_AbstractLock()->obj_node()->eqv_uncast(obj)) {
2056         alock = o->as_AbstractLock();
2057         Node* box = alock->box_node();
2058         // Replace old box node with new eliminated box for all users
2059         // of the same object and mark related locks as eliminated.
2060         mark_eliminated_box(box, obj);
2061       }
2062     }
2063   }
2064 }
2065 
2066 // we have determined that this lock/unlock can be eliminated, we simply
2067 // eliminate the node without expanding it.
2068 //
2069 // Note:  The membar's associated with the lock/unlock are currently not
2070 //        eliminated.  This should be investigated as a future enhancement.
2071 //
2072 bool PhaseMacroExpand::eliminate_locking_node(AbstractLockNode *alock) {
2073 
2074   if (!alock->is_eliminated()) {
2075     return false;
2076   }
2077 #ifdef ASSERT
2078   if (!alock->is_coarsened()) {
2079     // Check that new "eliminated" BoxLock node is created.
2080     BoxLockNode* oldbox = alock->box_node()->as_BoxLock();
2081     assert(oldbox->is_eliminated(), "should be done already");
2082   }
2083 #endif
2084 
2085   alock->log_lock_optimization(C, "eliminate_lock");
2086 
2087 #ifndef PRODUCT
2088   if (PrintEliminateLocks) {
2089     tty->print_cr("++++ Eliminated: %d %s '%s'", alock->_idx, (alock->is_Lock() ? "Lock" : "Unlock"), alock->kind_as_string());
2090   }
2091 #endif
2092 
2093   Node* mem  = alock->in(TypeFunc::Memory);
2094   Node* ctrl = alock->in(TypeFunc::Control);
2095   guarantee(ctrl != NULL, "missing control projection, cannot replace_node() with NULL");
2096 
2097   alock->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2098   // There are 2 projections from the lock.  The lock node will
2099   // be deleted when its last use is subsumed below.
2100   assert(alock->outcnt() == 2 &&
2101          _callprojs.fallthrough_proj != NULL &&
2102          _callprojs.fallthrough_memproj != NULL,
2103          "Unexpected projections from Lock/Unlock");
2104 
2105   Node* fallthroughproj = _callprojs.fallthrough_proj;
2106   Node* memproj_fallthrough = _callprojs.fallthrough_memproj;
2107 
2108   // The memory projection from a lock/unlock is RawMem
2109   // The input to a Lock is merged memory, so extract its RawMem input
2110   // (unless the MergeMem has been optimized away.)
2111   if (alock->is_Lock()) {
2112     // Search for MemBarAcquireLock node and delete it also.
2113     MemBarNode* membar = fallthroughproj->unique_ctrl_out()->as_MemBar();
2114     assert(membar != NULL && membar->Opcode() == Op_MemBarAcquireLock, "");
2115     Node* ctrlproj = membar->proj_out(TypeFunc::Control);
2116     Node* memproj = membar->proj_out(TypeFunc::Memory);
2117     _igvn.replace_node(ctrlproj, fallthroughproj);
2118     _igvn.replace_node(memproj, memproj_fallthrough);
2119 
2120     // Delete FastLock node also if this Lock node is unique user
2121     // (a loop peeling may clone a Lock node).
2122     Node* flock = alock->as_Lock()->fastlock_node();
2123     if (flock->outcnt() == 1) {
2124       assert(flock->unique_out() == alock, "sanity");
2125       _igvn.replace_node(flock, top());
2126     }
2127   }
2128 
2129   // Search for MemBarReleaseLock node and delete it also.
2130   if (alock->is_Unlock() && ctrl->is_Proj() && ctrl->in(0)->is_MemBar()) {
2131     MemBarNode* membar = ctrl->in(0)->as_MemBar();
2132     assert(membar->Opcode() == Op_MemBarReleaseLock &&
2133            mem->is_Proj() && membar == mem->in(0), "");
2134     _igvn.replace_node(fallthroughproj, ctrl);
2135     _igvn.replace_node(memproj_fallthrough, mem);
2136     fallthroughproj = ctrl;
2137     memproj_fallthrough = mem;
2138     ctrl = membar->in(TypeFunc::Control);
2139     mem  = membar->in(TypeFunc::Memory);
2140   }
2141 
2142   _igvn.replace_node(fallthroughproj, ctrl);
2143   _igvn.replace_node(memproj_fallthrough, mem);
2144   return true;
2145 }
2146 
2147 
2148 //------------------------------expand_lock_node----------------------
2149 void PhaseMacroExpand::expand_lock_node(LockNode *lock) {
2150 
2151   Node* ctrl = lock->in(TypeFunc::Control);
2152   Node* mem = lock->in(TypeFunc::Memory);
2153   Node* obj = lock->obj_node();
2154   Node* box = lock->box_node();
2155   Node* flock = lock->fastlock_node();
2156 
2157   assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2158 
2159   // Make the merge point
2160   Node *region;
2161   Node *mem_phi;
2162   Node *slow_path;
2163 
2164   region  = new RegionNode(3);
2165   // create a Phi for the memory state
2166   mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2167 
2168   // Optimize test; set region slot 2
2169   slow_path = opt_bits_test(ctrl, region, 2, flock, 0, 0);
2170   mem_phi->init_req(2, mem);
2171 
2172   // Make slow path call
2173   CallNode *call = make_slow_call((CallNode *) lock, OptoRuntime::complete_monitor_enter_Type(),
2174                                   OptoRuntime::complete_monitor_locking_Java(), NULL, slow_path,
2175                                   obj, box, NULL);
2176 
2177   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2178 
2179   // Slow path can only throw asynchronous exceptions, which are always
2180   // de-opted.  So the compiler thinks the slow-call can never throw an
2181   // exception.  If it DOES throw an exception we would need the debug
2182   // info removed first (since if it throws there is no monitor).
2183   assert(_callprojs.fallthrough_ioproj == NULL && _callprojs.catchall_ioproj == NULL &&
2184          _callprojs.catchall_memproj == NULL && _callprojs.catchall_catchproj == NULL, "Unexpected projection from Lock");
2185 
2186   // Capture slow path
2187   // disconnect fall-through projection from call and create a new one
2188   // hook up users of fall-through projection to region
2189   Node *slow_ctrl = _callprojs.fallthrough_proj->clone();
2190   transform_later(slow_ctrl);
2191   _igvn.hash_delete(_callprojs.fallthrough_proj);
2192   _callprojs.fallthrough_proj->disconnect_inputs(C);
2193   region->init_req(1, slow_ctrl);
2194   // region inputs are now complete
2195   transform_later(region);
2196   _igvn.replace_node(_callprojs.fallthrough_proj, region);
2197 
2198   Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory));
2199 
2200   mem_phi->init_req(1, memproj);
2201 
2202   transform_later(mem_phi);
2203 
2204   _igvn.replace_node(_callprojs.fallthrough_memproj, mem_phi);
2205 }
2206 
2207 //------------------------------expand_unlock_node----------------------
2208 void PhaseMacroExpand::expand_unlock_node(UnlockNode *unlock) {
2209 
2210   Node* ctrl = unlock->in(TypeFunc::Control);
2211   Node* mem = unlock->in(TypeFunc::Memory);
2212   Node* obj = unlock->obj_node();
2213   Node* box = unlock->box_node();
2214 
2215   assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2216 
2217   // No need for a null check on unlock
2218 
2219   // Make the merge point
2220   Node *region;
2221   Node *mem_phi;
2222 
2223   region  = new RegionNode(3);
2224   // create a Phi for the memory state
2225   mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2226 
2227   FastUnlockNode *funlock = new FastUnlockNode( ctrl, obj, box );
2228   funlock = transform_later( funlock )->as_FastUnlock();
2229   // Optimize test; set region slot 2
2230   Node *slow_path = opt_bits_test(ctrl, region, 2, funlock, 0, 0);
2231   Node *thread = transform_later(new ThreadLocalNode());
2232 
2233   CallNode *call = make_slow_call((CallNode *) unlock, OptoRuntime::complete_monitor_exit_Type(),
2234                                   CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_unlocking_C),
2235                                   "complete_monitor_unlocking_C", slow_path, obj, box, thread);
2236 
2237   call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2238   assert(_callprojs.fallthrough_ioproj == NULL && _callprojs.catchall_ioproj == NULL &&
2239          _callprojs.catchall_memproj == NULL && _callprojs.catchall_catchproj == NULL, "Unexpected projection from Lock");
2240 
2241   // No exceptions for unlocking
2242   // Capture slow path
2243   // disconnect fall-through projection from call and create a new one
2244   // hook up users of fall-through projection to region
2245   Node *slow_ctrl = _callprojs.fallthrough_proj->clone();
2246   transform_later(slow_ctrl);
2247   _igvn.hash_delete(_callprojs.fallthrough_proj);
2248   _callprojs.fallthrough_proj->disconnect_inputs(C);
2249   region->init_req(1, slow_ctrl);
2250   // region inputs are now complete
2251   transform_later(region);
2252   _igvn.replace_node(_callprojs.fallthrough_proj, region);
2253 
2254   Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory) );
2255   mem_phi->init_req(1, memproj );
2256   mem_phi->init_req(2, mem);
2257   transform_later(mem_phi);
2258 
2259   _igvn.replace_node(_callprojs.fallthrough_memproj, mem_phi);
2260 }
2261 
2262 void PhaseMacroExpand::expand_subtypecheck_node(SubTypeCheckNode *check) {
2263   assert(check->in(SubTypeCheckNode::Control) == NULL, "should be pinned");
2264   Node* bol = check->unique_out();
2265   Node* obj_or_subklass = check->in(SubTypeCheckNode::ObjOrSubKlass);
2266   Node* superklass = check->in(SubTypeCheckNode::SuperKlass);
2267   assert(bol->is_Bool() && bol->as_Bool()->_test._test == BoolTest::ne, "unexpected bool node");
2268 
2269   for (DUIterator_Last imin, i = bol->last_outs(imin); i >= imin; --i) {
2270     Node* iff = bol->last_out(i);
2271     assert(iff->is_If(), "where's the if?");
2272 
2273     if (iff->in(0)->is_top()) {
2274       _igvn.replace_input_of(iff, 1, C->top());
2275       continue;
2276     }
2277 
2278     Node* iftrue = iff->as_If()->proj_out(1);
2279     Node* iffalse = iff->as_If()->proj_out(0);
2280     Node* ctrl = iff->in(0);
2281 
2282     Node* subklass = NULL;
2283     if (_igvn.type(obj_or_subklass)->isa_klassptr()) {
2284       subklass = obj_or_subklass;
2285     } else {
2286       Node* k_adr = basic_plus_adr(obj_or_subklass, oopDesc::klass_offset_in_bytes());
2287       subklass = _igvn.transform(LoadKlassNode::make(_igvn, NULL, C->immutable_memory(), k_adr, TypeInstPtr::KLASS));
2288     }
2289 
2290     Node* not_subtype_ctrl = Phase::gen_subtype_check(subklass, superklass, &ctrl, NULL, _igvn);
2291 
2292     _igvn.replace_input_of(iff, 0, C->top());
2293     _igvn.replace_node(iftrue, not_subtype_ctrl);
2294     _igvn.replace_node(iffalse, ctrl);
2295   }
2296   _igvn.replace_node(check, C->top());
2297 }
2298 
2299 //---------------------------eliminate_macro_nodes----------------------
2300 // Eliminate scalar replaced allocations and associated locks.
2301 void PhaseMacroExpand::eliminate_macro_nodes() {
2302   if (C->macro_count() == 0)
2303     return;
2304   NOT_PRODUCT(int membar_before = count_MemBar(C);)
2305 
2306   // Before elimination may re-mark (change to Nested or NonEscObj)
2307   // all associated (same box and obj) lock and unlock nodes.
2308   int cnt = C->macro_count();
2309   for (int i=0; i < cnt; i++) {
2310     Node *n = C->macro_node(i);
2311     if (n->is_AbstractLock()) { // Lock and Unlock nodes
2312       mark_eliminated_locking_nodes(n->as_AbstractLock());
2313     }
2314   }
2315   // Re-marking may break consistency of Coarsened locks.
2316   if (!C->coarsened_locks_consistent()) {
2317     return; // recompile without Coarsened locks if broken
2318   }
2319 
2320   // First, attempt to eliminate locks
2321   bool progress = true;
2322   while (progress) {
2323     progress = false;
2324     for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
2325       Node* n = C->macro_node(i - 1);
2326       bool success = false;
2327       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2328       if (n->is_AbstractLock()) {
2329         success = eliminate_locking_node(n->as_AbstractLock());
2330 #ifndef PRODUCT
2331         if (success && PrintOptoStatistics) {
2332           Atomic::inc(&PhaseMacroExpand::_monitor_objects_removed_counter);
2333         }
2334 #endif
2335       }
2336       assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
2337       progress = progress || success;
2338     }
2339   }
2340   // Next, attempt to eliminate allocations
2341   _has_locks = false;
2342   progress = true;
2343   while (progress) {
2344     progress = false;
2345     for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
2346       Node* n = C->macro_node(i - 1);
2347       bool success = false;
2348       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2349       switch (n->class_id()) {
2350       case Node::Class_Allocate:
2351       case Node::Class_AllocateArray:
2352         success = eliminate_allocate_node(n->as_Allocate());
2353 #ifndef PRODUCT
2354         if (success && PrintOptoStatistics) {
2355           Atomic::inc(&PhaseMacroExpand::_objs_scalar_replaced_counter);
2356         }
2357 #endif
2358         break;
2359       case Node::Class_CallStaticJava:
2360         success = eliminate_boxing_node(n->as_CallStaticJava());
2361         break;
2362       case Node::Class_Lock:
2363       case Node::Class_Unlock:
2364         assert(!n->as_AbstractLock()->is_eliminated(), "sanity");
2365         _has_locks = true;
2366         break;
2367       case Node::Class_ArrayCopy:
2368         break;
2369       case Node::Class_OuterStripMinedLoop:
2370         break;
2371       case Node::Class_SubTypeCheck:
2372         break;
2373       case Node::Class_Opaque1:
2374         break;
2375       default:
2376         assert(n->Opcode() == Op_LoopLimit ||
2377                n->Opcode() == Op_Opaque2   ||
2378                n->Opcode() == Op_Opaque3   ||
2379                n->Opcode() == Op_Opaque4   ||
2380                BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(n),
2381                "unknown node type in macro list");
2382       }
2383       assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
2384       progress = progress || success;
2385     }
2386   }
2387 #ifndef PRODUCT
2388   if (PrintOptoStatistics) {
2389     int membar_after = count_MemBar(C);
2390     Atomic::add(&PhaseMacroExpand::_memory_barriers_removed_counter, membar_before - membar_after);
2391   }
2392 #endif
2393 }
2394 
2395 //------------------------------expand_macro_nodes----------------------
2396 //  Returns true if a failure occurred.
2397 bool PhaseMacroExpand::expand_macro_nodes() {
2398   // Last attempt to eliminate macro nodes.
2399   eliminate_macro_nodes();
2400   if (C->failing())  return true;
2401 
2402   // Eliminate Opaque and LoopLimit nodes. Do it after all loop optimizations.
2403   bool progress = true;
2404   while (progress) {
2405     progress = false;
2406     for (int i = C->macro_count(); i > 0; i--) {
2407       Node* n = C->macro_node(i-1);
2408       bool success = false;
2409       DEBUG_ONLY(int old_macro_count = C->macro_count();)
2410       if (n->Opcode() == Op_LoopLimit) {
2411         // Remove it from macro list and put on IGVN worklist to optimize.
2412         C->remove_macro_node(n);
2413         _igvn._worklist.push(n);
2414         success = true;
2415       } else if (n->Opcode() == Op_CallStaticJava) {
2416         // Remove it from macro list and put on IGVN worklist to optimize.
2417         C->remove_macro_node(n);
2418         _igvn._worklist.push(n);
2419         success = true;
2420       } else if (n->is_Opaque1() || n->Opcode() == Op_Opaque2) {
2421         _igvn.replace_node(n, n->in(1));
2422         success = true;
2423 #if INCLUDE_RTM_OPT
2424       } else if ((n->Opcode() == Op_Opaque3) && ((Opaque3Node*)n)->rtm_opt()) {
2425         assert(C->profile_rtm(), "should be used only in rtm deoptimization code");
2426         assert((n->outcnt() == 1) && n->unique_out()->is_Cmp(), "");
2427         Node* cmp = n->unique_out();
2428 #ifdef ASSERT
2429         // Validate graph.
2430         assert((cmp->outcnt() == 1) && cmp->unique_out()->is_Bool(), "");
2431         BoolNode* bol = cmp->unique_out()->as_Bool();
2432         assert((bol->outcnt() == 1) && bol->unique_out()->is_If() &&
2433                (bol->_test._test == BoolTest::ne), "");
2434         IfNode* ifn = bol->unique_out()->as_If();
2435         assert((ifn->outcnt() == 2) &&
2436                ifn->proj_out(1)->is_uncommon_trap_proj(Deoptimization::Reason_rtm_state_change) != NULL, "");
2437 #endif
2438         Node* repl = n->in(1);
2439         if (!_has_locks) {
2440           // Remove RTM state check if there are no locks in the code.
2441           // Replace input to compare the same value.
2442           repl = (cmp->in(1) == n) ? cmp->in(2) : cmp->in(1);
2443         }
2444         _igvn.replace_node(n, repl);
2445         success = true;
2446 #endif
2447       } else if (n->Opcode() == Op_Opaque4) {
2448         // With Opaque4 nodes, the expectation is that the test of input 1
2449         // is always equal to the constant value of input 2. So we can
2450         // remove the Opaque4 and replace it by input 2. In debug builds,
2451         // leave the non constant test in instead to sanity check that it
2452         // never fails (if it does, that subgraph was constructed so, at
2453         // runtime, a Halt node is executed).
2454 #ifdef ASSERT
2455         _igvn.replace_node(n, n->in(1));
2456 #else
2457         _igvn.replace_node(n, n->in(2));
2458 #endif
2459         success = true;
2460       } else if (n->Opcode() == Op_OuterStripMinedLoop) {
2461         n->as_OuterStripMinedLoop()->adjust_strip_mined_loop(&_igvn);
2462         C->remove_macro_node(n);
2463         success = true;
2464       }
2465       assert(!success || (C->macro_count() == (old_macro_count - 1)), "elimination must have deleted one node from macro list");
2466       progress = progress || success;
2467     }
2468   }
2469 
2470   // Clean up the graph so we're less likely to hit the maximum node
2471   // limit
2472   _igvn.set_delay_transform(false);
2473   _igvn.optimize();
2474   if (C->failing())  return true;
2475   _igvn.set_delay_transform(true);
2476 
2477 
2478   // Because we run IGVN after each expansion, some macro nodes may go
2479   // dead and be removed from the list as we iterate over it. Move
2480   // Allocate nodes (processed in a second pass) at the beginning of
2481   // the list and then iterate from the last element of the list until
2482   // an Allocate node is seen. This is robust to random deletion in
2483   // the list due to nodes going dead.
2484   C->sort_macro_nodes();
2485 
2486   // expand arraycopy "macro" nodes first
2487   // For ReduceBulkZeroing, we must first process all arraycopy nodes
2488   // before the allocate nodes are expanded.
2489   while (C->macro_count() > 0) {
2490     int macro_count = C->macro_count();
2491     Node * n = C->macro_node(macro_count-1);
2492     assert(n->is_macro(), "only macro nodes expected here");
2493     if (_igvn.type(n) == Type::TOP || (n->in(0) != NULL && n->in(0)->is_top())) {
2494       // node is unreachable, so don't try to expand it
2495       C->remove_macro_node(n);
2496       continue;
2497     }
2498     if (n->is_Allocate()) {
2499       break;
2500     }
2501     // Make sure expansion will not cause node limit to be exceeded.
2502     // Worst case is a macro node gets expanded into about 200 nodes.
2503     // Allow 50% more for optimization.
2504     if (C->check_node_count(300, "out of nodes before macro expansion")) {
2505       return true;
2506     }
2507 
2508     DEBUG_ONLY(int old_macro_count = C->macro_count();)
2509     switch (n->class_id()) {
2510     case Node::Class_Lock:
2511       expand_lock_node(n->as_Lock());
2512       break;
2513     case Node::Class_Unlock:
2514       expand_unlock_node(n->as_Unlock());
2515       break;
2516     case Node::Class_ArrayCopy:
2517       expand_arraycopy_node(n->as_ArrayCopy());
2518       break;
2519     case Node::Class_SubTypeCheck:
2520       expand_subtypecheck_node(n->as_SubTypeCheck());
2521       break;
2522     default:
2523       assert(false, "unknown node type in macro list");
2524     }
2525     assert(C->macro_count() == (old_macro_count - 1), "expansion must have deleted one node from macro list");
2526     if (C->failing())  return true;
2527 
2528     // Clean up the graph so we're less likely to hit the maximum node
2529     // limit
2530     _igvn.set_delay_transform(false);
2531     _igvn.optimize();
2532     if (C->failing())  return true;
2533     _igvn.set_delay_transform(true);
2534   }
2535 
2536   // All nodes except Allocate nodes are expanded now. There could be
2537   // new optimization opportunities (such as folding newly created
2538   // load from a just allocated object). Run IGVN.
2539 
2540   // expand "macro" nodes
2541   // nodes are removed from the macro list as they are processed
2542   while (C->macro_count() > 0) {
2543     int macro_count = C->macro_count();
2544     Node * n = C->macro_node(macro_count-1);
2545     assert(n->is_macro(), "only macro nodes expected here");
2546     if (_igvn.type(n) == Type::TOP || (n->in(0) != NULL && n->in(0)->is_top())) {
2547       // node is unreachable, so don't try to expand it
2548       C->remove_macro_node(n);
2549       continue;
2550     }
2551     // Make sure expansion will not cause node limit to be exceeded.
2552     // Worst case is a macro node gets expanded into about 200 nodes.
2553     // Allow 50% more for optimization.
2554     if (C->check_node_count(300, "out of nodes before macro expansion")) {
2555       return true;
2556     }
2557     switch (n->class_id()) {
2558     case Node::Class_Allocate:
2559       expand_allocate(n->as_Allocate());
2560       break;
2561     case Node::Class_AllocateArray:
2562       expand_allocate_array(n->as_AllocateArray());
2563       break;
2564     default:
2565       assert(false, "unknown node type in macro list");
2566     }
2567     assert(C->macro_count() < macro_count, "must have deleted a node from macro list");
2568     if (C->failing())  return true;
2569 
2570     // Clean up the graph so we're less likely to hit the maximum node
2571     // limit
2572     _igvn.set_delay_transform(false);
2573     _igvn.optimize();
2574     if (C->failing())  return true;
2575     _igvn.set_delay_transform(true);
2576   }
2577 
2578   _igvn.set_delay_transform(false);
2579   return false;
2580 }
2581 
2582 #ifndef PRODUCT
2583 int PhaseMacroExpand::_objs_scalar_replaced_counter = 0;
2584 int PhaseMacroExpand::_monitor_objects_removed_counter = 0;
2585 int PhaseMacroExpand::_GC_barriers_removed_counter = 0;
2586 int PhaseMacroExpand::_memory_barriers_removed_counter = 0;
2587 
2588 void PhaseMacroExpand::print_statistics() {
2589   tty->print("Objects scalar replaced = %d, ", Atomic::load(&_objs_scalar_replaced_counter));
2590   tty->print("Monitor objects removed = %d, ", Atomic::load(&_monitor_objects_removed_counter));
2591   tty->print("GC barriers removed = %d, ", Atomic::load(&_GC_barriers_removed_counter));
2592   tty->print_cr("Memory barriers removed = %d", Atomic::load(&_memory_barriers_removed_counter));
2593 }
2594 
2595 int PhaseMacroExpand::count_MemBar(Compile *C) {
2596   if (!PrintOptoStatistics) {
2597     return 0;
2598   }
2599   Unique_Node_List ideal_nodes;
2600   int total = 0;
2601   ideal_nodes.map(C->live_nodes(), NULL);
2602   ideal_nodes.push(C->root());
2603   for (uint next = 0; next < ideal_nodes.size(); ++next) {
2604     Node* n = ideal_nodes.at(next);
2605     if (n->is_MemBar()) {
2606       total++;
2607     }
2608     for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2609       Node* m = n->fast_out(i);
2610       ideal_nodes.push(m);
2611     }
2612   }
2613   return total;
2614 }
2615 #endif
--- EOF ---